From 595ce48eb2be88a42ceb33865c337020a328a4dd Mon Sep 17 00:00:00 2001
From: Dion Dokter <diondokter@gmail.com>
Date: Wed, 25 Dec 2024 22:54:48 +0100
Subject: [PATCH] Write the flag sooner with a known value

---
 embassy-stm32/src/lib.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/embassy-stm32/src/lib.rs b/embassy-stm32/src/lib.rs
index 3c7f96bb1..857090303 100644
--- a/embassy-stm32/src/lib.rs
+++ b/embassy-stm32/src/lib.rs
@@ -350,6 +350,11 @@ mod dual_core {
     pub fn init_primary(config: Config, shared_data: &'static MaybeUninit<SharedData>) -> Peripherals {
         let shared_data = unsafe { shared_data.assume_init_ref() };
 
+        // Write the flag as soon as possible. Reading this flag uninitialized in the `init_secondary`
+        // is maybe unsound? Unclear. If it is indeed unsound, writing it sooner doesn't fix it all,
+        // but improves the odds of it going right
+        shared_data.init_flag.store(0, Ordering::SeqCst);
+
         rcc::set_freqs_ptr(shared_data.clocks.get());
         let p = init_hw(config);