diff --git a/BETA b/BETA
deleted file mode 100644
index e69de29bb..000000000
diff --git a/MAJOR_VERSION b/MAJOR_VERSION
deleted file mode 100644
index 45a4fb75d..000000000
--- a/MAJOR_VERSION
+++ /dev/null
@@ -1 +0,0 @@
-8
diff --git a/artiq/_version.py b/artiq/_version.py
index b3c3d5be4..e308ce8c2 100644
--- a/artiq/_version.py
+++ b/artiq/_version.py
@@ -1,13 +1,4 @@
 import os
 
 def get_version():
-    override = os.getenv("VERSIONEER_OVERRIDE")
-    if override:
-      return override
-    srcroot = os.path.join(os.path.dirname(os.path.abspath(__file__)), os.pardir)
-    with open(os.path.join(srcroot, "MAJOR_VERSION"), "r") as f:
-        version = f.read().strip()
-    version += ".unknown"
-    if os.path.exists(os.path.join(srcroot, "BETA")):
-        version += ".beta"
-    return version
+    return os.getenv("VERSIONEER_OVERRIDE", default="8.0.beta")
diff --git a/artiq/examples/kc705_nist_clock/repository/precompile.py b/artiq/examples/kc705_nist_clock/repository/precompile.py
new file mode 100644
index 000000000..6bfaaf057
--- /dev/null
+++ b/artiq/examples/kc705_nist_clock/repository/precompile.py
@@ -0,0 +1,20 @@
+from artiq.experiment import *
+
+
+class Precompile(EnvExperiment):
+    def build(self):
+        self.setattr_device("core")
+        self.hello_str = "hello ARTIQ"
+
+    def prepare(self):
+    	self.precompiled = self.core.precompile(self.hello, "world")
+
+    @kernel
+    def hello(self, arg):
+    	print(self.hello_str, arg)
+    	self.hello_str = "nowriteback"
+
+    def run(self):
+        self.precompiled()
+        self.hello_str = "noupdate"
+        self.precompiled()
diff --git a/artiq/firmware/runtime/kern_hwreq.rs b/artiq/firmware/runtime/kern_hwreq.rs
index a80a7b71a..952a18439 100644
--- a/artiq/firmware/runtime/kern_hwreq.rs
+++ b/artiq/firmware/runtime/kern_hwreq.rs
@@ -116,8 +116,8 @@ mod remote_i2c {
         }
     }
 
-    pub fn switch_select(io: &Io, aux_mutex: &Mutex, linkno: u8, destination: u8, busno: u8, address: u8, mask: u8) -> Result<u8, &'static str> {
-        let reply = drtio::aux_transact(io, aux_mutex, linkno, &drtioaux::Packet::I2cPca954xSelectRequest {
+    pub fn switch_select(io: &Io, aux_mutex: &Mutex, linkno: u8, destination: u8, busno: u8, address: u8, mask: u8) -> Result<(), &'static str> {
+        let reply = drtio::aux_transact(io, aux_mutex, linkno, &drtioaux::Packet::I2cSwitchSelectRequest {
             destination: destination,
             busno: busno,
             address: address,
diff --git a/artiq/test/coredevice/test_i2c.py b/artiq/test/coredevice/test_i2c.py
index 7b589cb4e..e8293db9d 100644
--- a/artiq/test/coredevice/test_i2c.py
+++ b/artiq/test/coredevice/test_i2c.py
@@ -3,7 +3,7 @@ import os, unittest
 from artiq.experiment import *
 from artiq.test.hardware_testbench import ExperimentCase
 from artiq.coredevice.exceptions import I2CError
-from artiq.coredevice.i2c import I2CSwitch
+from artiq.coredevice.i2c import I2CSwitch, i2c_read_byte
 
 
 class I2CSwitchTest(EnvExperiment):
@@ -16,7 +16,9 @@ class I2CSwitchTest(EnvExperiment):
         passed = True
         for i in range(8):
             self.i2c_switch.set(i)
-            if self.i2c_switch.readback() != 1 << i:
+            # this will work only with pca9548 (like on kc705)
+            # otherwise we cannot guarantee exact readback values
+            if i2c_read_byte(self.i2c_switch.busno, self.i2c_switch.address) != 1 << i:
                 passed = False
         self.set_dataset("passed", passed)
 
diff --git a/versioneer.py b/versioneer.py
index 20794abc9..f6393d21e 100644
--- a/versioneer.py
+++ b/versioneer.py
@@ -11,16 +11,7 @@ def get_rev():
 """
 
 def get_version():
-    override = os.getenv("VERSIONEER_OVERRIDE")
-    if override:
-      return override
-    srcroot = os.path.dirname(os.path.abspath(__file__))
-    with open(os.path.join(srcroot, "MAJOR_VERSION"), "r") as f:
-        version = f.read().strip()
-    version += ".0"
-    if os.path.exists(os.path.join(srcroot, "BETA")):
-        version += ".beta"
-    return version
+    return os.getenv("VERSIONEER_OVERRIDE", default="8.0.beta")
 
 def get_rev():
     return os.getenv("VERSIONEER_REV", default="unknown")