From ecb77073577c54d8ec78313f477dc8034005d90c Mon Sep 17 00:00:00 2001
From: ju6ge <judge@felixrichter.tech>
Date: Mon, 4 May 2026 02:31:49 +0200
Subject: [PATCH] fix: add gpio_pad_hold on GPIO21 to prevent boot ROM from
 reconfiguring shift register enable pin

---
 rust/src/hal/v3_hal.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/rust/src/hal/v3_hal.rs b/rust/src/hal/v3_hal.rs
index 643a861..5135323 100644
--- a/rust/src/hal/v3_hal.rs
+++ b/rust/src/hal/v3_hal.rs
@@ -140,9 +140,11 @@ pub(crate) fn create_v3(
     let mut general_fault = Output::new(peripherals.gpio6, Level::Low, OutputConfig::default());
     general_fault.set_low();
 
+    hold_disable(21);
     let mut shift_register_enable_invert =
         Output::new(peripherals.gpio21, Level::Low, OutputConfig::default());
     shift_register_enable_invert.set_low();
+    hold_enable(21);
 
     let signal_counter = peripherals.pcnt0;