Need dump for it. Dump on device is crashed.
What are the symptoms?
A common cause is a corrupted or missing PTB partition.
You could confirm if this is the case using 'show ptb' an the Amboot prompt.
It should list the partitions - if not, ptb is corrupt.
I can post some simple instructions here if you want to try recovering it.
I do also have a flash .bin image though I cannot be sure what the exact model was except 'Mini PTZ V2' as I only had the board itself.
The missing ptb can be fixed with a sneaky trick.
The Amboot environment variables resides in the same flash partition as the 'dtb' data
The fix is to
tftp load to a specific memory location a copy of the dtb data (a few kB) and do a dummy 'setenv' to write the flash.