diff --git a/artiq/coredevice/ad9154_spi.py b/artiq/coredevice/ad9154_spi.py
index 0ebb77034..d83a85ff6 100644
--- a/artiq/coredevice/ad9154_spi.py
+++ b/artiq/coredevice/ad9154_spi.py
@@ -10,9 +10,8 @@ class AD9154:
         self.chip_select = chip_select
 
     @kernel
-    def setup_bus(self, write_div=16, read_div=16):
-        self.bus.set_config_mu(0, write_div, read_div)
-        self.bus.set_xfer(self.chip_select, 24, 0)
+    def setup_bus(self, div=16):
+        self.bus.set_config_mu(0, 24, div, self.chip_select)
 
     @kernel
     def write(self, addr, data):
diff --git a/artiq/coredevice/spi.py b/artiq/coredevice/spi.py
index 1d60722d5..b10d9dd0d 100644
--- a/artiq/coredevice/spi.py
+++ b/artiq/coredevice/spi.py
@@ -21,7 +21,7 @@ __all__ = [
     "SPI_OFFLINE", "SPI_ACTIVE", "SPI_PENDING",
     "SPI_CS_POLARITY", "SPI_CLK_POLARITY", "SPI_CLK_PHASE",
     "SPI_LSB_FIRST", "SPI_HALF_DUPLEX",
-    "SPIMaster", "NRTSPIMaster"
+    "SPIMaster"
 ]
 
 
@@ -284,65 +284,3 @@ class SPIMaster:
         rtio_output(now_mu(), self.channel, SPI_CONFIG_ADDR | SPI_RT2WB_READ,
                     0)
         return rtio_input_data(self.channel)
-
-
-@syscall(flags={"nounwind", "nowrite"})
-def spi_set_config(busno: TInt32, flags: TInt32, write_div: TInt32, read_div: TInt32) -> TNone:
-    raise NotImplementedError("syscall not simulated")
-
-
-@syscall(flags={"nounwind", "nowrite"})
-def spi_set_xfer(busno: TInt32, chip_select: TInt32, write_length: TInt32, read_length: TInt32) -> TNone:
-    raise NotImplementedError("syscall not simulated")
-
-
-@syscall(flags={"nounwind", "nowrite"})
-def spi_write(busno: TInt32, data: TInt32) -> TNone:
-    raise NotImplementedError("syscall not simulated")
-
-
-@syscall(flags={"nounwind", "nowrite"})
-def spi_read(busno: TInt32) -> TInt32:
-    raise NotImplementedError("syscall not simulated")
-
-
-class NRTSPIMaster:
-    """Core device non-realtime Serial Peripheral Interface (SPI) bus master.
-    Owns one non-realtime SPI bus.
-
-    With this driver, SPI transactions and are performed by the CPU without
-    involving RTIO.
-
-    Realtime and non-realtime buses are separate and defined at bitstream
-    compilation time.
-
-    See :class:`SPIMaster` for a description of the methods.
-    """
-    def __init__(self, dmgr, busno=0, core_device="core"):
-        self.core = dmgr.get(core_device)
-        self.busno = busno
-
-    @kernel
-    def set_config_mu(self, flags=0, write_div=6, read_div=6):
-        """Set the ``config`` register.
-
-        Note that the non-realtime SPI cores are usually clocked by the system
-        clock and not the RTIO clock. In many cases, the SPI configuration is
-        already set by the firmware and you do not need to call this method.
-
-        The offline bit cannot be set using this method.
-        The SPI bus is briefly taken offline when this method is called.
-        """
-        spi_set_config(self.busno, flags, write_div, read_div)
-
-    @kernel
-    def set_xfer(self, chip_select=0, write_length=0, read_length=0):
-        spi_set_xfer(self.busno, chip_select, write_length, read_length)
-
-    @kernel
-    def write(self, data=0):
-        spi_write(self.busno, data)
-
-    @kernel
-    def read(self):
-        return spi_read(self.busno)
diff --git a/artiq/coredevice/spi2.py b/artiq/coredevice/spi2.py
index ddf81d477..31e1effa2 100644
--- a/artiq/coredevice/spi2.py
+++ b/artiq/coredevice/spi2.py
@@ -8,6 +8,7 @@ time is an error.
 """
 
 from artiq.language.core import syscall, kernel, portable, now_mu, delay_mu
+from artiq.language.types import TInt32, TNone
 from artiq.coredevice.rtio import rtio_output, rtio_input_data
 
 
@@ -16,7 +17,7 @@ __all__ = [
     "SPI_OFFLINE", "SPI_END", "SPI_INPUT",
     "SPI_CS_POLARITY", "SPI_CLK_POLARITY", "SPI_CLK_PHASE",
     "SPI_LSB_FIRST", "SPI_HALF_DUPLEX",
-    "SPIMaster"
+    "SPIMaster", "NRTSPIMaster"
 ]
 
 SPI_DATA_ADDR = 0
@@ -205,3 +206,53 @@ class SPIMaster:
         :return: SPI input data.
         """
         return rtio_input_data(self.channel)
+
+
+@syscall(flags={"nounwind", "nowrite"})
+def spi_set_config(busno: TInt32, flags: TInt32, length: TInt32, div: TInt32, cs: TInt32) -> TNone:
+    raise NotImplementedError("syscall not simulated")
+
+
+@syscall(flags={"nounwind", "nowrite"})
+def spi_write(busno: TInt32, data: TInt32) -> TNone:
+    raise NotImplementedError("syscall not simulated")
+
+
+@syscall(flags={"nounwind", "nowrite"})
+def spi_read(busno: TInt32) -> TInt32:
+    raise NotImplementedError("syscall not simulated")
+
+
+class NRTSPIMaster:
+    """Core device non-realtime Serial Peripheral Interface (SPI) bus master.
+    Owns one non-realtime SPI bus.
+
+    With this driver, SPI transactions and are performed by the CPU without
+    involving RTIO.
+
+    Realtime and non-realtime buses are separate and defined at bitstream
+    compilation time.
+
+    See :class:`SPIMaster` for a description of the methods.
+    """
+    def __init__(self, dmgr, busno=0, core_device="core"):
+        self.core = dmgr.get(core_device)
+        self.busno = busno
+
+    @kernel
+    def set_config_mu(self, flags=0, length=8, div=6, cs=1):
+        """Set the ``config`` register.
+
+        Note that the non-realtime SPI cores are usually clocked by the system
+        clock and not the RTIO clock. In many cases, the SPI configuration is
+        already set by the firmware and you do not need to call this method.
+        """
+        spi_set_config(self.busno, flags, length, div, cs)
+
+    @kernel
+    def write(self, data=0):
+        spi_write(self.busno, data)
+
+    @kernel
+    def read(self):
+        return spi_read(self.busno)
diff --git a/artiq/examples/sayma_drtio/device_db.py b/artiq/examples/sayma_drtio/device_db.py
index 039efb6bd..92b7dd13d 100644
--- a/artiq/examples/sayma_drtio/device_db.py
+++ b/artiq/examples/sayma_drtio/device_db.py
@@ -95,7 +95,7 @@ device_db = {
 
     "converter_spi": {
         "type": "local",
-        "module": "artiq.coredevice.spi",
+        "module": "artiq.coredevice.spi2",
         "class": "NRTSPIMaster",
     },
     "ad9154_spi0": {
@@ -112,7 +112,7 @@ device_db = {
     },
     "rconverter_spi": {
         "type": "local",
-        "module": "artiq.coredevice.spi",
+        "module": "artiq.coredevice.spi2",
         "class": "NRTSPIMaster",
         "arguments": {"busno": 0x010000}
     },
diff --git a/artiq/examples/sayma_standalone/device_db.py b/artiq/examples/sayma_standalone/device_db.py
index 370b3f0a6..303fdce7e 100644
--- a/artiq/examples/sayma_standalone/device_db.py
+++ b/artiq/examples/sayma_standalone/device_db.py
@@ -21,7 +21,7 @@ device_db = {
 
     "converter_spi": {
         "type": "local",
-        "module": "artiq.coredevice.spi",
+        "module": "artiq.coredevice.spi2",
         "class": "NRTSPIMaster",
     },
     "ad9154_spi0": {
diff --git a/artiq/firmware/ksupport/api.rs b/artiq/firmware/ksupport/api.rs
index 53736a0fa..b2d608b1f 100644
--- a/artiq/firmware/ksupport/api.rs
+++ b/artiq/firmware/ksupport/api.rs
@@ -118,7 +118,6 @@ static mut API: &'static [(&'static str, *const ())] = &[
     api!(i2c_read = ::nrt_bus::i2c::read),
 
     api!(spi_set_config = ::nrt_bus::spi::set_config),
-    api!(spi_set_xfer = ::nrt_bus::spi::set_xfer),
     api!(spi_write = ::nrt_bus::spi::write),
     api!(spi_read = ::nrt_bus::spi::read),
 ];
diff --git a/artiq/firmware/ksupport/nrt_bus.rs b/artiq/firmware/ksupport/nrt_bus.rs
index c847bcf82..9e226dd96 100644
--- a/artiq/firmware/ksupport/nrt_bus.rs
+++ b/artiq/firmware/ksupport/nrt_bus.rs
@@ -50,17 +50,9 @@ pub mod spi {
     use ::recv;
     use kernel_proto::*;
 
-    pub extern fn set_config(busno: i32, flags: i32, write_div: i32, read_div: i32) {
+    pub extern fn set_config(busno: i32, flags: i32, length: i32, div: i32, cs: i32) {
         send(&SpiSetConfigRequest { busno: busno as u32, flags: flags as u8,
-                                    write_div: write_div as u8, read_div: read_div as u8 });
-        recv!(&SpiBasicReply { succeeded } => if !succeeded {
-            raise!("SPIError", "SPI bus could not be accessed");
-        });
-    }
-
-    pub extern fn set_xfer(busno: i32, chip_select: i32, write_length: i32, read_length: i32) {
-        send(&SpiSetXferRequest { busno: busno as u32, chip_select: chip_select as u16,
-                                  write_length: write_length as u8, read_length: read_length as u8 });
+                                    length: length as u8, div: div as u8, cs: cs as u8 });
         recv!(&SpiBasicReply { succeeded } => if !succeeded {
             raise!("SPIError", "SPI bus could not be accessed");
         });
diff --git a/artiq/firmware/libboard_artiq/ad9154.rs b/artiq/firmware/libboard_artiq/ad9154.rs
index d00f2fc40..a50d55ab8 100644
--- a/artiq/firmware/libboard_artiq/ad9154.rs
+++ b/artiq/firmware/libboard_artiq/ad9154.rs
@@ -3,34 +3,33 @@ use ad9154_reg;
 
 fn spi_setup(dacno: u8) {
     unsafe {
-        csr::converter_spi::offline_write(1);
+        while csr::converter_spi::idle_read() == 0 {}
+        csr::converter_spi::offline_write(0);
+        csr::converter_spi::end_write(1);
         csr::converter_spi::cs_polarity_write(0b0001);
         csr::converter_spi::clk_polarity_write(0);
         csr::converter_spi::clk_phase_write(0);
         csr::converter_spi::lsb_first_write(0);
         csr::converter_spi::half_duplex_write(0);
-        csr::converter_spi::clk_div_write_write(16);
-        csr::converter_spi::clk_div_read_write(16);
-        csr::converter_spi::xfer_len_write_write(24);
-        csr::converter_spi::xfer_len_read_write(0);
+        csr::converter_spi::length_write(24 - 1);
+        csr::converter_spi::div_write(16 - 2);
         csr::converter_spi::cs_write(1 << (csr::CONFIG_CONVERTER_SPI_FIRST_AD9154_CS + dacno as u32));
-        csr::converter_spi::offline_write(0);
     }
 }
 
 fn write(addr: u16, data: u8) {
     unsafe {
-        csr::converter_spi::data_write_write(
+        while csr::converter_spi::writable_read() == 0 {}
+        csr::converter_spi::data_write(
             ((addr as u32) << 16) | ((data as u32) << 8));
-        while csr::converter_spi::pending_read() != 0 {}
-        while csr::converter_spi::active_read() != 0 {}
+        while csr::converter_spi::writable_read() == 0 {}
     }
 }
 
 fn read(addr: u16) -> u8 {
     unsafe {
         write((1 << 15) | addr, 0);
-        csr::converter_spi::data_read_read() as u8
+        csr::converter_spi::data_read() as u8
     }
 }
 
diff --git a/artiq/firmware/libboard_artiq/hmc830_7043.rs b/artiq/firmware/libboard_artiq/hmc830_7043.rs
index 80406251c..dc899ce15 100644
--- a/artiq/firmware/libboard_artiq/hmc830_7043.rs
+++ b/artiq/firmware/libboard_artiq/hmc830_7043.rs
@@ -51,16 +51,24 @@ mod hmc830 {
 
     fn spi_setup() {
         unsafe {
-            csr::converter_spi::offline_write(1);
+            while csr::converter_spi::idle_read() == 0 {}
+            csr::converter_spi::offline_write(0);
+            csr::converter_spi::end_write(1);
             csr::converter_spi::cs_polarity_write(0b0001);
             csr::converter_spi::clk_polarity_write(0);
             csr::converter_spi::clk_phase_write(0);
             csr::converter_spi::lsb_first_write(0);
             csr::converter_spi::half_duplex_write(0);
-            csr::converter_spi::clk_div_write_write(8);
-            csr::converter_spi::clk_div_read_write(8);
+            csr::converter_spi::div_write(16 - 2);
             csr::converter_spi::cs_write(1 << csr::CONFIG_CONVERTER_SPI_HMC830_CS);
-            csr::converter_spi::offline_write(0);
+
+            // do a dummy cycle with cs still high to ensure Open mode
+            // (rising CLK before rising CS)
+            csr::converter_spi::length_write(0);
+            csr::converter_spi::data_write(0);
+            while csr::converter_spi::writable_read() == 0 {}
+
+            csr::converter_spi::length_write(31 - 1);
         }
     }
 
@@ -68,24 +76,17 @@ mod hmc830 {
         let cmd = (0 << 6) | addr;
         let val = ((cmd as u32) << 24) | data;
         unsafe {
-            csr::converter_spi::xfer_len_write_write(32);
-            csr::converter_spi::xfer_len_read_write(0);
-            csr::converter_spi::data_write_write(val << (32-31));
-            while csr::converter_spi::pending_read() != 0 {}
-            while csr::converter_spi::active_read() != 0 {}
+            while csr::converter_spi::writable_read() == 0 {}
+            csr::converter_spi::data_write(val << 1);
+            while csr::converter_spi::writable_read() == 0 {}
         }
     }
 
     fn read(addr: u8) -> u32 {
-        let cmd = (1 << 6) | addr;
-        let val = (cmd as u32) << 24;
+        write(addr, 0);
         unsafe {
-            csr::converter_spi::xfer_len_write_write(7);
-            csr::converter_spi::xfer_len_read_write(25);
-            csr::converter_spi::data_write_write(val << (32-31));
-            while csr::converter_spi::pending_read() != 0 {}
-            while csr::converter_spi::active_read() != 0 {}
-            csr::converter_spi::data_read_read() & 0xffffff
+            while csr::converter_spi::writable_read() == 0 {}
+            csr::converter_spi::data_read() & 0xffffff
         }
     }
 
@@ -123,7 +124,7 @@ mod hmc830 {
 
 mod hmc7043 {
     use board::csr;
-    
+
     // To do: check which output channels we actually need
     const DAC_CLK_DIV: u32 = 2;
     const FPGA_CLK_DIV: u32 = 8;
@@ -150,16 +151,17 @@ mod hmc7043 {
 
     fn spi_setup() {
         unsafe {
-            csr::converter_spi::offline_write(1);
+            while csr::converter_spi::idle_read() == 0 {}
+            csr::converter_spi::offline_write(0);
+            csr::converter_spi::end_write(1);
             csr::converter_spi::cs_polarity_write(0b0001);
             csr::converter_spi::clk_polarity_write(0);
             csr::converter_spi::clk_phase_write(0);
             csr::converter_spi::lsb_first_write(0);
-            csr::converter_spi::half_duplex_write(1);
-            csr::converter_spi::clk_div_write_write(8);
-            csr::converter_spi::clk_div_read_write(8);
+            csr::converter_spi::half_duplex_write(0);  // change mid-transaction for reads
+            csr::converter_spi::length_write(24 - 1);
+            csr::converter_spi::div_write(16 - 2);
             csr::converter_spi::cs_write(1 << csr::CONFIG_CONVERTER_SPI_HMC7043_CS);
-            csr::converter_spi::offline_write(0);
         }
     }
 
@@ -167,24 +169,29 @@ mod hmc7043 {
         let cmd = (0 << 15) | addr;
         let val = ((cmd as u32) << 8) | data as u32;
         unsafe {
-            csr::converter_spi::xfer_len_write_write(24);
-            csr::converter_spi::xfer_len_read_write(0);
-            csr::converter_spi::data_write_write(val << (32-24));
-            while csr::converter_spi::pending_read() != 0 {}
-            while csr::converter_spi::active_read() != 0 {}
+            while csr::converter_spi::writable_read() == 0 {}
+            csr::converter_spi::data_write(val << 8);
+            while csr::converter_spi::writable_read() == 0 {}
         }
     }
 
     fn read(addr: u16) -> u8 {
         let cmd = (1 << 15) | addr;
-        let val = (cmd as u32) << 8;
+        let val = cmd as u32;
         unsafe {
-            csr::converter_spi::xfer_len_write_write(16);
-            csr::converter_spi::xfer_len_read_write(8);
-            csr::converter_spi::data_write_write(val << (32-24));
-            while csr::converter_spi::pending_read() != 0 {}
-            while csr::converter_spi::active_read() != 0 {}
-            csr::converter_spi::data_read_read() as u8
+            while csr::converter_spi::writable_read() == 0 {}
+            csr::converter_spi::end_write(0);
+            csr::converter_spi::length_write(16 - 1);
+            csr::converter_spi::data_write(val << 16);
+            while csr::converter_spi::writable_read() == 0 {}
+            csr::converter_spi::end_write(1);
+            csr::converter_spi::half_duplex_write(1);
+            csr::converter_spi::length_write(8 - 1);
+            csr::converter_spi::data_write(0);
+            while csr::converter_spi::writable_read() == 0 {}
+            csr::converter_spi::half_duplex_write(0);
+            csr::converter_spi::length_write(24 - 1);
+            csr::converter_spi::data_read() as u8
         }
     }
 
@@ -233,7 +240,7 @@ mod hmc7043 {
             write(channel_base + 0x4, dphase & 0x1f);
 
             // No analog phase shift on clock channels
-            if (channel % 2) == 0 { write(channel_base + 0x7, 0x00); } 
+            if (channel % 2) == 0 { write(channel_base + 0x7, 0x00); }
             else { write(channel_base + 0x7, 0x01); }
 
             write(channel_base + 0x8, 0x08)
@@ -245,6 +252,7 @@ mod hmc7043 {
 
 pub fn init() -> Result<(), &'static str> {
     clock_mux::init();
+    /* must be the first SPI init because of HMC830 SPI mode selection */
     hmc830::init()?;
     hmc7043::init()
 }
diff --git a/artiq/firmware/libboard_artiq/spi.rs b/artiq/firmware/libboard_artiq/spi.rs
index 44aa0c729..94773b690 100644
--- a/artiq/firmware/libboard_artiq/spi.rs
+++ b/artiq/firmware/libboard_artiq/spi.rs
@@ -2,33 +2,24 @@
 mod imp {
     use board::csr;
 
-    pub fn set_config(busno: u8, flags: u8, write_div: u8, read_div: u8) -> Result<(), ()> {
+    pub fn set_config(busno: u8, flags: u8, length: u8, div: u8, cs: u8) -> Result<(), ()> {
         if busno != 0 {
             return Err(())
         }
         unsafe {
-            csr::converter_spi::offline_write(1);
-            csr::converter_spi::cs_polarity_write(flags >> 3 & 1);
+            while csr::converter_spi::idle_read() == 0 {}
+            csr::converter_spi::offline_write(flags >> 0 & 1);
+            csr::converter_spi::end_write(flags >> 1 & 1);
+            /* input (in RTIO): flags >> 2 & 1 */
+            /* cs_polarity is a mask in the CSR interface */
+            csr::converter_spi::cs_polarity_write(0xff & (flags >> 3 & 1));
             csr::converter_spi::clk_polarity_write(flags >> 4 & 1);
             csr::converter_spi::clk_phase_write(flags >> 5 & 1);
             csr::converter_spi::lsb_first_write(flags >> 6 & 1);
             csr::converter_spi::half_duplex_write(flags >> 7 & 1);
-            csr::converter_spi::clk_div_write_write(write_div);
-            csr::converter_spi::clk_div_read_write(read_div);
-            csr::converter_spi::offline_write(0);
-        }
-        Ok(())
-    }
-
-    pub fn set_xfer(busno: u8, chip_select: u16, write_length: u8, read_length: u8)
-                   -> Result<(), ()> {
-        if busno != 0 {
-            return Err(())
-        }
-        unsafe {
-            csr::converter_spi::cs_write(chip_select as _);
-            csr::converter_spi::xfer_len_write_write(write_length);
-            csr::converter_spi::xfer_len_read_write(read_length);
+            csr::converter_spi::length_write(length - 1);
+            csr::converter_spi::div_write(div - 2);
+            csr::converter_spi::cs_write(cs);
         }
         Ok(())
     }
@@ -38,9 +29,9 @@ mod imp {
             return Err(())
         }
         unsafe {
-            csr::converter_spi::data_write_write(data);
-            while csr::converter_spi::pending_read() != 0 {}
-            while csr::converter_spi::active_read() != 0 {}
+            while csr::converter_spi::writable_read() == 0 {}
+            csr::converter_spi::data_write(data);
+            while csr::converter_spi::writable_read() == 0 {}
         }
         Ok(())
     }
@@ -50,16 +41,14 @@ mod imp {
             return Err(())
         }
         Ok(unsafe {
-            csr::converter_spi::data_read_read()
+            csr::converter_spi::data_read()
         })
     }
 }
 
 #[cfg(not(has_converter_spi))]
 mod imp {
-    pub fn set_config(_busno: u8, _flags: u8, _write_div: u8, _read_div: u8) -> Result<(), ()> { Err(()) }
-    pub fn set_xfer(_busno: u8,_chip_select: u16, _write_length: u8, _read_length: u8)
-                   -> Result<(), ()> { Err(()) }
+    pub fn set_config(_busno: u8, _flags: u8, _length: u8, _div: u8, _cs: u8) -> Result<(), ()> { Err(()) }
     pub fn write(_busno: u8,_data: u32) -> Result<(), ()> { Err(()) }
     pub fn read(_busno: u8,) -> Result<u32, ()> { Err(()) }
 }
diff --git a/artiq/firmware/libdrtioaux/lib.rs b/artiq/firmware/libdrtioaux/lib.rs
index 927825630..bb4aa6dcc 100644
--- a/artiq/firmware/libdrtioaux/lib.rs
+++ b/artiq/firmware/libdrtioaux/lib.rs
@@ -41,8 +41,7 @@ pub enum Packet {
     I2cReadReply { succeeded: bool, data: u8 },
     I2cBasicReply { succeeded: bool },
 
-    SpiSetConfigRequest { busno: u8, flags: u8, write_div: u8, read_div: u8 },
-    SpiSetXferRequest { busno: u8, chip_select: u16, write_length: u8, read_length: u8 },
+    SpiSetConfigRequest { busno: u8, flags: u8, length: u8, div: u8, cs: u8 },
     SpiWriteRequest { busno: u8, data: u32 },
     SpiReadRequest { busno: u8 },
     SpiReadReply { succeeded: bool, data: u32 },
@@ -123,15 +122,11 @@ impl Packet {
             0x90 => Packet::SpiSetConfigRequest {
                 busno: read_u8(reader)?,
                 flags: read_u8(reader)?,
-                write_div: read_u8(reader)?,
-                read_div: read_u8(reader)?
-            },
-            0x91 => Packet::SpiSetXferRequest {
-                busno: read_u8(reader)?,
-                chip_select: read_u16(reader)?,
-                write_length: read_u8(reader)?,
-                read_length: read_u8(reader)?
+                length: read_u8(reader)?,
+                div: read_u8(reader)?,
+                cs: read_u8(reader)?
             },
+            /* 0x91: was Packet::SpiSetXferRequest */
             0x92 => Packet::SpiWriteRequest {
                 busno: read_u8(reader)?,
                 data: read_u32(reader)?
@@ -238,19 +233,13 @@ impl Packet {
                 write_bool(writer, succeeded)?;
             },
 
-            Packet::SpiSetConfigRequest { busno, flags, write_div, read_div } => {
+            Packet::SpiSetConfigRequest { busno, flags, length, div, cs } => {
                 write_u8(writer, 0x90)?;
                 write_u8(writer, busno)?;
                 write_u8(writer, flags)?;
-                write_u8(writer, write_div)?;
-                write_u8(writer, read_div)?;
-            },
-            Packet::SpiSetXferRequest { busno, chip_select, write_length, read_length } => {
-                write_u8(writer, 0x91)?;
-                write_u8(writer, busno)?;
-                write_u16(writer, chip_select)?;
-                write_u8(writer, write_length)?;
-                write_u8(writer, read_length)?;
+                write_u8(writer, length)?;
+                write_u8(writer, div)?;
+                write_u8(writer, cs)?;
             },
             Packet::SpiWriteRequest { busno, data } => {
                 write_u8(writer, 0x92)?;
diff --git a/artiq/firmware/libproto/kernel_proto.rs b/artiq/firmware/libproto/kernel_proto.rs
index 06e5473d0..babd9fbcf 100644
--- a/artiq/firmware/libproto/kernel_proto.rs
+++ b/artiq/firmware/libproto/kernel_proto.rs
@@ -85,8 +85,7 @@ pub enum Message<'a> {
     I2cReadReply { succeeded: bool, data: u8 },
     I2cBasicReply { succeeded: bool },
 
-    SpiSetConfigRequest { busno: u32, flags: u8, write_div: u8, read_div: u8 },
-    SpiSetXferRequest { busno: u32, chip_select: u16, write_length: u8, read_length: u8 },
+    SpiSetConfigRequest { busno: u32, flags: u8, length: u8, div: u8, cs: u8 },
     SpiWriteRequest { busno: u32, data: u32 },
     SpiReadRequest { busno: u32 },
     SpiReadReply { succeeded: bool, data: u32 },
diff --git a/artiq/firmware/runtime/kern_hwreq.rs b/artiq/firmware/runtime/kern_hwreq.rs
index 8eea9cd17..be1a380e8 100644
--- a/artiq/firmware/runtime/kern_hwreq.rs
+++ b/artiq/firmware/runtime/kern_hwreq.rs
@@ -194,25 +194,13 @@ mod drtio_spi {
         }
     }
 
-    pub fn set_config(nodeno: u8, busno: u8, flags: u8, write_div: u8, read_div: u8) -> Result<(), ()> {
+    pub fn set_config(nodeno: u8, busno: u8, flags: u8, length: u8, div: u8, cs: u8) -> Result<(), ()> {
         let request = drtioaux::Packet::SpiSetConfigRequest {
             busno: busno,
             flags: flags,
-            write_div: write_div,
-            read_div: read_div
-        };
-        if drtioaux::hw::send(nodeno, &request).is_err() {
-            return Err(())
-        }
-        basic_reply(nodeno)
-    }
-
-    pub fn set_xfer(nodeno: u8, busno: u8, chip_select: u16, write_length: u8, read_length: u8) -> Result<(), ()> {
-        let request = drtioaux::Packet::SpiSetXferRequest {
-            busno: busno,
-            chip_select: chip_select,
-            write_length: write_length,
-            read_length: read_length
+            length: length,
+            div: div,
+            cs: cs
         };
         if drtioaux::hw::send(nodeno, &request).is_err() {
             return Err(())
@@ -255,12 +243,7 @@ mod drtio_spi {
 #[cfg(not(has_drtio))]
 mod drtio_spi {
     pub fn set_config(_nodeno: u8, _busno: u8, _flags: u8,
-                      _write_div: u8, _read_div: u8) -> Result<(), ()> {
-        Err(())
-    }
-
-    pub fn set_xfer(_nodeno: u8, _busno: u8, _chip_select: u16,
-                    _write_length: u8, _read_length: u8) -> Result<(), ()> {
+                      _length: u8, _div: u8, _cs: u8) -> Result<(), ()> {
         Err(())
     }
 
@@ -277,23 +260,13 @@ mod spi {
     use board_artiq::spi as local_spi;
     use super::drtio_spi;
 
-    pub fn set_config(busno: u32, flags: u8, write_div: u8, read_div: u8) -> Result<(), ()> {
+    pub fn set_config(busno: u32, flags: u8, length: u8, div: u8, cs: u8) -> Result<(), ()> {
         let nodeno = (busno >> 16) as u8;
         let node_busno = busno as u8;
         if nodeno == 0 {
-            local_spi::set_config(node_busno, flags, write_div, read_div)
+            local_spi::set_config(node_busno, flags, length, div, cs)
         } else {
-            drtio_spi::set_config(nodeno, node_busno, flags, write_div, read_div)
-        }
-    }
-
-    pub fn set_xfer(busno: u32, chip_select: u16, write_length: u8, read_length: u8) -> Result<(), ()> {
-        let nodeno = (busno >> 16) as u8;
-        let node_busno = busno as u8;
-        if nodeno == 0 {
-            local_spi::set_xfer(node_busno, chip_select, write_length, read_length)
-        } else {
-            drtio_spi::set_xfer(nodeno, node_busno, chip_select, write_length, read_length)
+            drtio_spi::set_config(nodeno, node_busno, flags, length, div, cs)
         }
     }
 
@@ -364,14 +337,10 @@ pub fn process_kern_hwreq(io: &Io, request: &kern::Message) -> io::Result<bool>
             }
         }
 
-        &kern::SpiSetConfigRequest { busno, flags, write_div, read_div } => {
-            let succeeded = spi::set_config(busno, flags, write_div, read_div).is_ok();
+        &kern::SpiSetConfigRequest { busno, flags, length, div, cs } => {
+            let succeeded = spi::set_config(busno, flags, length, div, cs).is_ok();
             kern_send(io, &kern::SpiBasicReply { succeeded: succeeded })
         },
-        &kern::SpiSetXferRequest { busno, chip_select, write_length, read_length } => {
-            let succeeded = spi::set_xfer(busno, chip_select, write_length, read_length).is_ok();
-            kern_send(io, &kern::SpiBasicReply { succeeded: succeeded })
-        }
         &kern::SpiWriteRequest { busno, data } => {
             let succeeded = spi::write(busno, data).is_ok();
             kern_send(io, &kern::SpiBasicReply { succeeded: succeeded })
diff --git a/artiq/firmware/runtime/main.rs b/artiq/firmware/runtime/main.rs
index 9cf3c11f3..3066ea9b3 100644
--- a/artiq/firmware/runtime/main.rs
+++ b/artiq/firmware/runtime/main.rs
@@ -94,6 +94,7 @@ fn startup() {
     #[cfg(si5324_as_synthesizer)]
     setup_si5324_as_synthesizer();
     #[cfg(has_hmc830_7043)]
+    /* must be the first SPI init because of HMC830 SPI mode selection */
     board_artiq::hmc830_7043::init().expect("cannot initialize HMC830/7043");
     #[cfg(has_ad9154)]
     board_artiq::ad9154::init().expect("cannot initialize AD9154");
diff --git a/artiq/firmware/satman/main.rs b/artiq/firmware/satman/main.rs
index 7744c65c0..195471457 100644
--- a/artiq/firmware/satman/main.rs
+++ b/artiq/firmware/satman/main.rs
@@ -144,14 +144,10 @@ fn process_aux_packet(p: &drtioaux::Packet) {
             };
         }
 
-        drtioaux::Packet::SpiSetConfigRequest { busno, flags, write_div, read_div } => {
-            let succeeded = spi::set_config(busno, flags, write_div, read_div).is_ok();
+        drtioaux::Packet::SpiSetConfigRequest { busno, flags, length, div, cs } => {
+            let succeeded = spi::set_config(busno, flags, length, div, cs).is_ok();
             drtioaux::hw::send_link(0, &drtioaux::Packet::SpiBasicReply { succeeded: succeeded }).unwrap();
         },
-        drtioaux::Packet::SpiSetXferRequest { busno, chip_select, write_length, read_length } => {
-            let succeeded = spi::set_xfer(busno, chip_select, write_length, read_length).is_ok();
-            drtioaux::hw::send_link(0, &drtioaux::Packet::SpiBasicReply { succeeded: succeeded }).unwrap();
-        }
         drtioaux::Packet::SpiWriteRequest { busno, data } => {
             let succeeded = spi::write(busno, data).is_ok();
             drtioaux::hw::send_link(0, &drtioaux::Packet::SpiBasicReply { succeeded: succeeded }).unwrap();
@@ -226,6 +222,7 @@ fn startup() {
     serwb::wait_init();
 
     #[cfg(has_hmc830_7043)]
+    /* must be the first SPI init because of HMC830 SPI mode selection */
     hmc830_7043::init().expect("cannot initialize HMC830/7043");
     i2c::init();
     si5324::setup(&SI5324_SETTINGS).expect("cannot initialize Si5324");
diff --git a/artiq/gateware/targets/sayma_rtm.py b/artiq/gateware/targets/sayma_rtm.py
index 9a77a4694..4061320ed 100755
--- a/artiq/gateware/targets/sayma_rtm.py
+++ b/artiq/gateware/targets/sayma_rtm.py
@@ -10,7 +10,7 @@ from migen.build.platforms.sinara import sayma_rtm
 from misoc.interconnect import wishbone, stream
 from misoc.interconnect.csr import *
 from misoc.cores import identifier
-from misoc.cores import spi
+from misoc.cores import spi2
 from misoc.cores import gpio
 from misoc.integration.wb_slaves import WishboneSlaveManager
 from misoc.integration.cpu_interface import get_csr_csv
@@ -140,10 +140,10 @@ class SaymaRTM(Module):
             platform.request("ad9154_txen", 1).eq(0b11)
         ]
 
-        self.submodules.converter_spi = spi.SPIMaster([
+        self.submodules.converter_spi = spi2.SPIMaster(spi2.SPIInterface(
             platform.request("hmc_spi"),
             platform.request("ad9154_spi", 0),
-            platform.request("ad9154_spi", 1)])
+            platform.request("ad9154_spi", 1)))
         csr_devices.append("converter_spi")
         self.comb += platform.request("hmc7043_reset").eq(0)