Unable to flash controller board

I have been trying to reset a bunch of controller boards that I can't seem to access at the moment and the reset button is not working on them so I downloaded the flash tool and firmware from Bitmain site and followed the guide.

After inserting the SD card to the miner the green status light flashes for around 2 min then turns solid for 1 Min then goes off for 30 seconds only to comes back on for 1 min in a never ending cycle of on-off (Green LED)

The site says that the green light will stop flashing once the flash is complete and to wait 1 min before power down. but the green light never goes off for more than 30 sec even after 1 hour of waiting it seems to be in a loop.

Has anyone come across this issue in the past and if so how did you get round the issue.

Thanks in advance.