I opened it up and attached to the serial console.
This is what is happening that is causing the sysupgrade to fail:
root@OpenWrt:/tmp# sysupgrade -n -v openwrt-ramips-mt7621-asus_rt-ax54-squashfs-sysupgrade.bin
Wed Apr 26 22:16:35 UTC 2023 upgrade: Commencing upgrade. Closing all shell sessions.
Watchdog handover: fd=3
- watchdog -
Watchdog does not have CARDRESET support
Wed Apr 26 22:16:36 UTC 2023 upgrade: Sending TERM to remaining processes ...
Wed Apr 26 22:16:40 UTC 2023 upgrade: Sending KILL to remaining processes ...
[ 114.049710] stage2 (3300): drop_caches: 3
Wed Apr 26 22:16:46 UTC 2023 upgrade: Switching to ramdisk...
Wed Apr 26 22:16:48 UTC 2023 upgrade: Performing system upgrade...
verifying sysupgrade tar file integrity
Unlocking kernel ...
Writing from <stdin> to kernel ...
[ 117.367835] ubi0: attaching mtd7
[ 117.473378] UBI: EOF marker found, PEBs from 31 will be erased
[ 118.023742] ubi0 error: ubi_io_is_bad: error -77 while checking if PEB 315 is bad
[ 118.031442] ubi0 error: ubi_attach_mtd_dev: failed to attach mtd7, error -77
ubiattach: error!: cannot attach mtd7
error 77 (Bad message)
ubiformat: mtd7 (nand), size 48234496 bytes (46.0 MiB), 368 eraseblocks of 131072 bytes (128.0 KiB), min. I/O size 2048 bytes
libscan: scanning eraseblock 183 -[ 118.883660] ubi0: attaching mtd7
libscan: scannin[ 118.990002] UBI: EOF marker found, PEBs from 31 will be erased
libscan: scanning eraseblock 31libmtd: error!: [ 119.541642] ubi0 error: ubi_io_is_bad: error -77 while checking if PEB 315 is bad
[ 119.549588] ubi0 error: ubi_attach_mtd_dev: failed to attach mtd7, error -77
ubiattach: error!: cannot attach mtd7
error 77 (Bad message)
cannot attach ubi mtd partition ubi
sysupgrade failed
Then the device reboots.
I have no experience with ubifs... Might I have a bad block in my flash or something that is causing this result?