Right, I did not answer because what you describe is not logically possible. You state you were in the official OS, had unpacked the Mer Firmware image into seperate parts (an unsupported method but nevertheless perfectly harmless). You clicked the initramfs.gz file, which is in fact not a gz file, but a uboot headered cpio archive gzipped, which at this point burnt out your hardware. Which is impossible unless you fell over a dd command, cpio extracted the result and then a solar flare killed your circuitry.

So, only logical explanation is a hardware issue - as the prelude for the error you described does not correspond with the outcome. And we can't help with hardware issues.