Hello everyone! I'm new to this forum with a serious problem. Today I have taken my Golf IV 1.8T AUQ to get it remapped by a local tuner with very good rep. He has deleted the SAI, EVAP and secondary labmda sensor from the software and the harware of the car. Then I asked him whether he can make a hard cut rev limiter on this ecu. He said that it will not be a problem and after about two hours the car was ready and was driving very well. However he told me that the hard cut rev can "fry"  the ECU if it is used often. I told him that I will not abuse the car everyday and that this is my daily car. So, I started the car from the shop, make sure that the limiter was there and poping  and returned home. When I was parking I noticed a kinda slight burning wires smell but I though that it was coming from outside. Locked the car, climbed the stairs happy and after an hour, I decided to take the car for a spin once again. Turned on the ignition... and the car wont start at all. I have tried about 34 million times with no success. The car has died completely. I have a VCDS 17.1, so I connected the cable and the ECU has stored 16985 Internal Control Module P0601 - 35-00 - Memory Check Sum error. The code cannot be deleted no matter what. I have disconected the battery terminals and bridget them for an hour with no success. Called the tuner and he told me that it is most probably the ECU. How can an ECU be fried from this hard cut super dooper rev limiter used 5 or 6 times? No matter, he warned me previously so its my fault...  So I towed the car back to the tuner in order to search for a solution. He put another ECU from a working car with the same part number, adaptated the immo to my key, with no success. The car cranks freely the rpm needle is showing the rpm vcds shows the rpm when cranking. Then he opened my ECU solder another chip for immo, I think, flashed the original map and now the checksum error does not appear. Car wont start again and now it is throwing ECM POWER RELAY OPEN CIRCUIT 17069 - P0685 ERROR. Changed the J271 relay... still nothing. All ECU fuses are fine. The coilpacks are not throwing spark. My questions is, is it the ECU that needs changing or there is something that can be done to it to fix it? Please help and thank you in advance!

Yeah he will not touch my car again that is for sure. What could be the problem? Any thoughts?

The last thing he did is to flash back the original file he extracted from the ECU before the remap and adapt the immobilizer with vcds because he tried to start the car with another ECU. He was recomended by a lot of people through out the forums in my country. He charged a bit more for the remap but I though it is worth it... well I was wrong. Basicly he returned the money but now I do not have a car and cannot rely on him. I will be very helpfull if someone give me any directions on where to start... Maybe I cannot explain everything down to the smallest detail but I'm trying my best. So,bBefore my car died I noticed a burning wires smell... Any ideas? Thank you!

You're asking us if we know what wires smell.  You're the one with the nose at the car, not us I'm afraid.  Have a look.

By "did have a look" I mean checked everything with a multimeter.

Can the original file/s from the ECU be wrong?

Did he ACTUALLY flash the original file though?  Did you see him save it and then re-upload the original, uneditted file?