It would be great if somebody knows a way to recover from this:
A failed firmware upgrade of a GSM7328S has ended up with the switch constantly outputting garbage characters over the serial console.
The switch was upgraded directly from 5.0.1.8 to 8.0.3.11.
Yes, I should've known, but this was done in a hurry.
The update to 8.0.3.11 went fine, but after reboot the switch stops at the Boot code screen:
1 - Start operational code.
2 - Start Boot Menu.
Starting the operational code fails.
From here we tried loading an older firmware version (6.0.0.15) over XMODEM. This fails with the following: "ERROR: Code image size of 1 bytes is invalid"
The last step in the bricking of this device was using the Netgear Serial Recovery Tool. The tool ran fine and updated to 7.2.0.5. However, the tests done after upgrade failed.
A reboot now results in the unit outputting a few characters of pure garbage at 1hz (once / sec) across the serial port.
Changing baud rates over the serial connection doesn't help - the characters are still garbage.
If anyone can help with this I'm eternally grateful
