dead nano clone 2gb white screen
 

Hi everybody!
i've killed my brand new nano clone..yesterday i had the stupid idea to upgrade the firmware..and then there were NO signs of life..
since half an hour he is showing a white screen and is displayed as ADFU device in windows..but i don't know, which is the right firmware or which could be one of the possible right ones...

inside i can read:
on one chip
hynix KOR
HY27UUO8AG5M
TPCB 748A

on another
AK1025
7HO16AB

and on the last
BL5767
01A3OK
cn070815
B-Link

on the board is written:
JB-308
07/09/19

and the display is type:
DMT0110BL-17-25-A 071119

I hope somebody can help me..he died so young..