diff --git a/artiq/firmware/Cargo.toml b/artiq/firmware/Cargo.toml
index 4aa1be734..705210ae1 100644
--- a/artiq/firmware/Cargo.toml
+++ b/artiq/firmware/Cargo.toml
@@ -2,4 +2,5 @@
 members = ["runtime", "ksupport", "satman"]
 
 [profile.dev]
-debug = 1 # either 0 or 2 cause an LLVM ICE
+incremental = false # incompatible with LTO
+debug = 2
diff --git a/artiq/firmware/ksupport/lib.rs b/artiq/firmware/ksupport/lib.rs
index d7ea126ae..945514a6f 100644
--- a/artiq/firmware/ksupport/lib.rs
+++ b/artiq/firmware/ksupport/lib.rs
@@ -229,15 +229,12 @@ const DMA_BUFFER_SIZE: usize = 64 * 1024;
 
 struct DmaRecorder {
     active:   bool,
-    #[allow(dead_code)]
-    padding:  [u8; 3], //https://github.com/rust-lang/rust/issues/41315
     data_len: usize,
     buffer:   [u8; DMA_BUFFER_SIZE],
 }
 
 static mut DMA_RECORDER: DmaRecorder = DmaRecorder {
     active:   false,
-    padding:  [0; 3],
     data_len: 0,
     buffer:   [0; DMA_BUFFER_SIZE],
 };
diff --git a/artiq/firmware/runtime/analyzer.rs b/artiq/firmware/runtime/analyzer.rs
index 1e2909a37..44ca2ed71 100644
--- a/artiq/firmware/runtime/analyzer.rs
+++ b/artiq/firmware/runtime/analyzer.rs
@@ -5,18 +5,13 @@ use analyzer_proto::*;
 
 const BUFFER_SIZE: usize = 512 * 1024;
 
-// hack until https://github.com/rust-lang/rust/issues/33626 is fixed
-#[repr(simd)]
-struct Align64(u64, u64, u64, u64, u64, u64, u64, u64);
-
+#[repr(align(64))]
 struct Buffer {
-    data: [u8; BUFFER_SIZE],
-    __alignment: [Align64; 0]
+    data: [u8; BUFFER_SIZE]
 }
 
 static mut BUFFER: Buffer = Buffer {
-    data: [0; BUFFER_SIZE],
-    __alignment: []
+    data: [0; BUFFER_SIZE]
 };
 
 fn arm() {
@@ -68,9 +63,6 @@ fn worker(stream: &mut TcpStream) -> io::Result<()> {
 }
 
 pub fn thread(io: Io) {
-    // verify that the hack above works
-    assert!(::core::mem::align_of::<Buffer>() == 64);
-
     let listener = TcpListener::new(&io, 65535);
     listener.listen(1382).expect("analyzer: cannot listen");
 
diff --git a/artiq/firmware/runtime/lib.rs b/artiq/firmware/runtime/lib.rs
index 8581224b7..ce6f9ee24 100644
--- a/artiq/firmware/runtime/lib.rs
+++ b/artiq/firmware/runtime/lib.rs
@@ -1,5 +1,5 @@
 #![no_std]
-#![feature(compiler_builtins_lib, alloc, repr_simd, lang_items, const_fn, global_allocator)]
+#![feature(compiler_builtins_lib, lang_items, alloc, global_allocator)]
 
 extern crate compiler_builtins;
 extern crate alloc;
diff --git a/conda/artiq-dev/meta.yaml b/conda/artiq-dev/meta.yaml
index 8c343decd..4ed09f11b 100644
--- a/conda/artiq-dev/meta.yaml
+++ b/conda/artiq-dev/meta.yaml
@@ -18,9 +18,9 @@ requirements:
     - misoc 0.11 py35_0+git3388e6ba
     - jesd204b 0.3
     - binutils-or1k-linux >=2.27
-    - llvm-or1k 4.0.1
-    - llvmlite-artiq 0.20.0
-    - rust-core-or1k 1.23.0 19
+    - llvm-or1k 6.0.0
+    - llvmlite-artiq 0.23.0.dev py35_2
+    - rust-core-or1k 1.25.0 20
     - openocd 0.10.0 1
     - lit
     - outputcheck
diff --git a/conda/artiq/meta.yaml b/conda/artiq/meta.yaml
index ce77a0b78..f629af85a 100644
--- a/conda/artiq/meta.yaml
+++ b/conda/artiq/meta.yaml
@@ -26,7 +26,7 @@ requirements:
     - setuptools 33.1.1
   run:
     - python >=3.5.3,<3.6
-    - llvmlite-artiq 0.20.0
+    - llvmlite-artiq 0.23.0.dev py35_2
     - binutils-or1k-linux >=2.27
     - pythonparser >=1.1
     - openocd 0.10.0 1