Possibly Bricked 5B?

#1

I have following problem:
After powerup, the LED is Green, no Blue blinking, no boot activity from uSD.
When I connect it to the computer, the RKDevTool says that device is in Mask Mode, even without the Mask button pressed.

Where is the problem?

#2

Your SPI is probably not flashed, and your SD card either has no bootloader on it, or the board is failing to read it.

Try flashing a bootloader image to SPI using RKDevTool.

#3

This means the 5B is alive. When there is nothing to boot, 5B will just go to maskrom mode.