OpenWrt One: auto-reboot after poweroff (watchdog related?)

Describe the bug

I have several OpenWrt One and am running stock OpenWrt 24.10.0, r28427-6df0e3d02a on them.

When I power down the device with the "poweroff" command, they power down as they should. But then after about 25 seconds they always restart.

This is how it looks like on the console (with timestamps added by tio):

[09:59:29.567] root@wlan-apnew1:~# poweroff
[09:59:37.738] root@wlan-apnew1:~# [  165.433727] br-lan: port 1(eth0) entered disabled state
[09:59:38.516] [  165.440270] mtk_soc_eth 15100000.ethernet eth0: left allmulticast mode
[09:59:38.522] [  165.446827] mtk_soc_eth 15100000.ethernet eth0: left promiscuous mode
[09:59:38.529] [  165.453323] br-lan: port 1(eth0) entered disabled state
[09:59:38.590] [  165.514119] mtk_soc_eth 15100000.ethernet eth0: Link is Down
[09:59:38.611] [  165.534815] mtk_soc_eth 15100000.ethernet eth1: left allmulticast mode
[09:59:38.617] [  165.541349] mtk_soc_eth 15100000.ethernet eth1: left promiscuous mode
[09:59:38.624] [  165.547865] br-lan: port 2(eth1) entered disabled state
[09:59:42.886] [  169.809647] reboot: Power down
[09:59:42.889] PANIC at PC : 0x00000000430047e4

[10:00:07.598] F0: 102B 0000
[10:00:07.599] FA: 1040 0000
[10:00:07.600] FA: 1040 0000 [0200]
[10:00:07.602] F9: 0000 0000
[10:00:07.604] V0: 0000 0000 [0001]
[10:00:07.605] 00: 0000 0000
[10:00:07.607] BP: 2400 0041 [0000]
[10:00:07.609] G0: 1190 0000
[10:00:07.610] EC: 0000 0000 [1000]
[10:00:07.612] T0: 0000 0244 [010F]
[10:00:07.614] Jump to BL

[10:00:07.616] NOTICE:  BL2: v2.10.0    (release):OpenWrt v2024.01.17~bacca82a-3 (mt7981-spim-nand-ubi-ddr4)
[10:00:07.624] NOTICE:  BL2: Built : 11:41:08, Dec  3 2024
[10:00:07.628] NOTICE:  WDT: Cold boot
[10:00:07.630] NOTICE:  WDT: disabled
[10:00:07.633] NOTICE:  EMI: Using DDR4 settings
[10:00:08.020] NOTICE:  EMI: Detected DRAM size: 1024MB
[10:00:08.038] NOTICE:  EMI: complex R/W mem test passed
[10:00:08.243] NOTICE:  CPU: MT7981 (1300MHz)
[...]

I have seen on the schematics that the OpenWrt One has a watchdog IC populated, EM6324QYSP5B-2.8+. According to the datasheet this model has a 25.6 seconds watchdog timer. This time would match to the reset I'm seeing.

So could it be that the watchdog isn't disabled on shutdown?

OpenWrt version

r28427-6df0e3d02a

OpenWrt release

24.10.0

OpenWrt target/subtarget

mediatek/filogic

Device

OpenWrt One

Image kind

Official downloaded image

Steps to reproduce

• Issue a "poweroff" command.
• Wait for the device to power off

Actual behaviour

• shutdown first
• but after about 25 seconds the device automatically restarts

Expected behaviour

Shutdown and the device then stays off permanently.

Additional info

No response

Diffconfig

Terms

• I am reporting an issue for OpenWrt, not an unsupported fork.

Start by tracing the OpenWrt One poweroff path and the watchdog handling around the reported “reboot: Power down” and PANIC output. Compare the roughly 25.6-second delay with the EM6324QYSP5B-2.8+ watchdog behavior; done means poweroff leaves the device off permanently, with a regression check for this hardware.