More than one week ago my customer brought in an iMac 21,5" 2017 for SSD upgrade. I've replaced HDD, cloned all data to new SSD and put everything back together, standard procedure. After few days customer informed me, that computer restarts randomly and then has problem to turn on showing weird loading screen. As system report says there were two errors, one about power button beeing pressed, second is CPU panic. In my service it sometimes turns on and works stable even for whole day, but if I will turn it off, most likely it won't turn on showing half progress bar screen (left or right side is completly empty, only backlight). I already have changed SSD with other one and replaced RAM modules - no changes. What can it be? Bad BIOS? I was searching for BIOS for this board, but I haven't found any trustful source.