diff --git a/core/embed/extmod/trezorobj.c b/core/embed/extmod/trezorobj.c
index 153930d01..13d153ff5 100644
--- a/core/embed/extmod/trezorobj.c
+++ b/core/embed/extmod/trezorobj.c
@@ -71,7 +71,7 @@ mp_obj_t trezor_obj_call_protected(void (*func)(void *), void *arg) {
   if (nlr_push(&nlr) == 0) {
     (*func)(arg);
     nlr_pop();
-    return mp_const_none;
+    return NULL;
   } else {
     return MP_OBJ_FROM_PTR(nlr.ret_val);
   }
diff --git a/core/embed/rust/src/micropython/runtime.rs b/core/embed/rust/src/micropython/runtime.rs
index fb4eccc7f..f71e17635 100644
--- a/core/embed/rust/src/micropython/runtime.rs
+++ b/core/embed/rust/src/micropython/runtime.rs
@@ -2,7 +2,7 @@ use core::mem::MaybeUninit;
 
 use crate::error::Error;
 
-use super::{ffi, obj::Obj};
+use super::ffi;
 
 /// Raise a micropython exception via NLR jump.
 /// Jumps directly out of the context without running any destructors,
@@ -34,7 +34,7 @@ where
         // boundary, so we assign it explicitly in `wrapper`.
         let mut result = MaybeUninit::zeroed();
         let mut wrapper = || {
-            result = MaybeUninit::new(func());
+            result.write(func());
         };
         // `wrapper` is a closure, and to pass it over the FFI, we split it into a
         // function pointer, and a user-data pointer.
@@ -42,7 +42,7 @@ where
         // `argument`.
         let (callback, argument) = split_func_into_callback_and_argument(&mut wrapper);
         let exception = ffi::trezor_obj_call_protected(Some(callback), argument);
-        if exception == Obj::const_none() {
+        if exception.is_null() {
             Ok(result.assume_init())
         } else {
             Err(Error::CaughtException(exception))
diff --git a/docs/core/build/emulator.md b/docs/core/build/emulator.md
index 6edc93014..8dee69c68 100644
--- a/docs/core/build/emulator.md
+++ b/docs/core/build/emulator.md
@@ -54,7 +54,7 @@ brew install scons sdl2 sdl2_image pkg-config llvm
 
 ## Rust
 
-You will require Rust and Cargo. The currently supported version is 1.52 stable.
+You will require Rust and Cargo. The currently supported version is 1.55 stable.
 The recommended way to install both is with [`rustup`](https://rustup.rs/). If you
 are installing `rustup` for the first time, the stable toolchain will be installed
 for you automatically. Otherwise, make sure you are up to date: