U-Boot autostarts the SoC watchdog (CONFIG_WATCHDOG_AUTOSTART default y) and services it from its main loop, but nothing services it after ExitBootServices()/bootm: an EFI-booted OS that does not take over the watchdog in time is reset mid-boot at a wall-clock-dependent point.
The MediaTek toprgu can count at most ~16 seconds, once firmware stops servicing it at the handoff, the OS has whatever is left of those 16 seconds. On the Genio 700 EVK the generic Ubuntu 26.04 arm64 image is hard-reset before its first boot reaches the login prompt: the mtk-wdt driver is a module loaded from the rootfs and cannot win that race. Nothing tells a generic OS that the watchdog is armed, so the failure is silent and, from the user's side, indistinguishable from broken firmware. Disable WATCHDOG_AUTOSTART for the Genio EVK boards (mt8365_evk directly, mt8188.config for the Genio 510/700). Signed-off-by: Carlo Caione <[email protected]> --- configs/mt8188.config | 1 + configs/mt8365_evk_defconfig | 1 + 2 files changed, 2 insertions(+) diff --git a/configs/mt8188.config b/configs/mt8188.config index 9dfba6bf99f..26823cf35d2 100644 --- a/configs/mt8188.config +++ b/configs/mt8188.config @@ -20,6 +20,7 @@ CONFIG_PINCTRL_MT8188=y CONFIG_BAUDRATE=921600 CONFIG_DM_SERIAL=y CONFIG_MTK_SERIAL=y +# CONFIG_WATCHDOG_AUTOSTART is not set CONFIG_WDT=y CONFIG_WDT_MTK=y # CONFIG_RANDOM_UUID is not set diff --git a/configs/mt8365_evk_defconfig b/configs/mt8365_evk_defconfig index 1a385492547..6620f540fd4 100644 --- a/configs/mt8365_evk_defconfig +++ b/configs/mt8365_evk_defconfig @@ -29,5 +29,6 @@ CONFIG_DM_REGULATOR_MT6357=y CONFIG_BAUDRATE=921600 CONFIG_DM_SERIAL=y CONFIG_MTK_SERIAL=y +# CONFIG_WATCHDOG_AUTOSTART is not set CONFIG_WDT=y CONFIG_WDT_MTK=y -- 2.55.0
