First, thanks for your kindly reply.

Second, i dont know how to find hwid as i cant turn on the unit. On the backside label doesn mention.

I downloaded the files you posted, first the 1091 and then tried the 827. Copy to sd.. /garmin put the sd on the unit, turn it on but didnt flash. Tried separately with both files. The same happens:

when in turn on the unit and in seconds shows "loading maps" but stops there and turns off. Seems that the unit doesnt go to read the sd?

on the back side label says 255w 1WM290037 dont know if tells you something.

Thanks in advance if you can help me with another step to try.

Note: opened the unit, unconect the battery for two hours and plug again. same thing happens.