Dual Ethernet Carrier Board locking up (Mini Router)

Mini router worked out of the box but would hang. Reflashing firmware was also problematic - rpi-imager would also hang or give write errors and the drive designator for the card would be intermittent. Don’t believe it is a PC issue or cable as it repeats on a different pc and cable. Any suggestions? Impossible to use as SD card is disabled in this unit. Thks

When I got it, the device had file system errors, have you tried repairing the file system using fsck?
But that should also have been fixed by re-flashing the OS on the CM4 eMMC. I did install the USB drivers but don’t actually use rpiboot or rpi-imager otherwise, after connecting the BOOT and GND pins it should just show up as a USB drive which you can flash with any imaging tool (I used balenaEtcher on Windows).

Yes, also noted file system errors but both repairing and reflashing resulted in the same hanging system. Tried flashing ubuntu and that showed many eMMC errors upon booting. Although rpiboot still works without error (and rpiboot -d recovery) , the disk now often doesn’t even appear or disappears quickly due to usb errors. Am attempting to secure a CM4 IO board to determine if the problem is in the CM4 or the carrier board but it looks like a show stopper hardware problem on our mini-router:(