Thread: Convert 3790/3760/3750 to 3490

even you have backup region 34 & 41, it's still 37xx or 34xx.

Legitimate question, but since everybody seemed to know already I did not think it was required...

Command format: ergn,<rgn #>

That looks like erase region, and a region number. This string can be found in boot.bin. Make a search for this unicode string.

Originally Posted by turboccc

Legitimate question, but since everybody seemed to know already I did not think it was required...
Command format: ergn,<rgn #>
That looks like erase region, and a region number. This string can be found in boot.bin. Make a search for this unicode string.

I know this command, but what will be with UnitID and HWID?

I would guess that HWID will be the one from the FW.
I would guess that the UnitID will be the one from region 34.

I thought the goal was to erase region 41, not 34. Erasing 34 will keep the same UnitID as it will be coming from region 41.

I would suggest to do those 3 commands at the same time:

write region 34 with offset 0x10-0x1f with FF, keep UnitID intact.
erase region 41
reboot

That should wipe clean your NVM and preserve your UnitID.

On my 3750, regions 45, 76, 139 to 143 are filled with FF only. Maybe try an erase on them? Make backups first!

Careful! We are in uncharted territory here.

Edit: region 76 seems to be empty on 3450 (0 byte in size).

Originally Posted by turboccc

On my 3750, regions 45, 76, 139 to 143 are filled with FF only. Maybe try an erase on them? Make backups first!
Careful! We are in uncharted territory here.
Edit: region 76 seems to be empty on 3450 (0 byte in size).

After disaster when modifying region 41 I will wait for a while. Maybe there is a safer solution to recover HWID.
Maybe somebody know why I lost HWID. Maybe I modified somehow protected region 41 area?

@voyager56

All experiment done with 37xx or in 34xx?
I just realize the dump region 43 from same unit with different firmware is much different.