820-3476-a serial unavailable.

MegaObi

New member
this one come in for liquid spill but nothing on board got affected. turns out power on but lcd dead. ordered one supplier sent 2015 lcd. so i put another working lcd (belongs to my machine) boot up and everything working but serial is unavailable. I plugged in medusa and to read bios put it over to pc wrote serial back and no boot. I tried clean bios same issue.

what am i doing wrong. can anyone help.

the only one strange thing i can see is the production date looks messed up.
 
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2informaticos

Administrator
Staff member
Medusa has a fix checksum option; try it after serial was changed.
I hope you verified backup has been correctly read.
 

2informaticos

Administrator
Staff member
You've probably wrote bad BIOS back to MLB.
Or got an error reading original chip.
Always verify first reading against original chip.
You may now need to build new BIOS dump...
Upload the dump actually flashed on the MLB.
 
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MegaObi

New member
Hey informaticos, thanks for your help I rewrote the bios again, was chiming bot still no boot, then I re-wrote serial then fix ME region but now booting working and serial is back!!!
 

2informaticos

Administrator
Staff member
Glad to hear that.

Remember, always verify the first reading for a backup BIOS.
Never erase/flash the chip before assure a correct reading!!!
 

MegaObi

New member
OK so i inspected around spi rom chip and im missing r6131.

EDIT: checked another board and it is probably no stuff but it doesnt say on schematics - got rolled
 
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2informaticos

Administrator
Staff member
Schematic specifies DUAL_IO and QUAD_IO versions.
R6131 is for QUAD_IO, which was for testing purposes, not implemented in that MLB.

As I told before, change U6100 with another chip.
This way you can discard an internal issue...
 

MegaObi

New member
Changed bios, programmed serial. everything working. i do pram reset again serial is gone!
 
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MegaObi

New member
Did you fix Fsys checksum after serial was changed?
after i programmed serial serial was showing with unhappy face. I then fixed fsys and got the smiley face. everything else was good vss fsys serial. again boot to os. serial everything displays fine. i do a few resets ... serial disappears.
 
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