Got my screen back. Eventually it was not working because I disconnected the battery. Once I soldered it back (OMG, two wires are so close to each other on PCB without any housing - OUCHHHH) the I saw the image. 99% there with repairment - however one more thing to do. As I connect USB, the screen goes darker and the USB/Battery indicator keeps flashing. The battery is not charging obviously, so I blame the U1 lipo charding IC - I guess it’s dead. As soon as I find replacement I will resolder it and hope everything will be Okay.
If anyone is interested in a “HOWTO” and a DFU bootloader for DSO Nano (V2), let me know. Probably it is already available somewhere but I didn’t manage to find one and had to compile myself.