I had this same problem and Bitmain are sending me a replacement board for free even thought it was my mistake 
I think your controller board is defective, if you still have a warranty with Bitmain, try to create a repair ticket and send that controller board to them to repair or replace a new one. Check both of your fans and all of the hashboards were working well before the firmware accident, if one of them is defective, then send the defective one with your controller board in one trip.
Had you tried the SD card recovery? https://bitmainhelp.zendesk.com/hc/en-us/articles/115000216034-L3-L3-Control-Board-Program-Recovery
Hi all,
I hope that you can help me !!!!!
I accidentally flash my L3+ with the D3 update from Blissz.....
When i discoverd that, i flash it back with the update from Bitmain for the L3+.
After that it does not see the hashboards anymore.. ALL 4...
Has anyone an idea what i can do?
?
NEED help....
https://imgur.com/JaKvrxwI hope that you can help me !!!!!
I accidentally flash my L3+ with the D3 update from Blissz.....
When i discoverd that, i flash it back with the update from Bitmain for the L3+.
After that it does not see the hashboards anymore.. ALL 4...
Has anyone an idea what i can do?
?NEED help....
I think your controller board is defective, if you still have a warranty with Bitmain, try to create a repair ticket and send that controller board to them to repair or replace a new one. Check both of your fans and all of the hashboards were working well before the firmware accident, if one of them is defective, then send the defective one with your controller board in one trip.
Had you tried the SD card recovery? https://bitmainhelp.zendesk.com/hc/en-us/articles/115000216034-L3-L3-Control-Board-Program-Recovery