diff --git a/zephcore/sysbuild/mcuboot.conf b/zephcore/sysbuild/mcuboot.conf
index 692620f..b1ed31d 100644
--- a/zephcore/sysbuild/mcuboot.conf
+++ b/zephcore/sysbuild/mcuboot.conf
@@ -23,5 +23,10 @@ CONFIG_LOG_DEFAULT_LEVEL=3
 # Disable to avoid spi_context build errors with minimal threading config.
 CONFIG_SPI=n
 
+# MCUboot doesn't need power domain management — some boards (e.g. Heltec V3)
+# have power-domain-gpio DTS nodes whose driver calls k_can_yield() which is
+# unavailable in MCUboot's minimal kernel.
+CONFIG_POWER_DOMAIN=n
+
 # ESP32 HAL's mcuboot_config.h is patched (patches/modules/hal/espressif/...)
 # to respect Zephyr Kconfig: mbedTLS detection, AUTO sector count, slot0 validation.