User Fox_Exe has unbricking directions for both first gen and second gen single bay My Cloud units. See the following for the second gen v2.x single bay My Cloud directions.
There are two different directions in those unbricking links. One uses Telnet and a USB flash drive. The other method involves extracting the second gen single bay My Cloud hard drive, attaching it to a computer using a USB to SATA adapter (or similar connection). Then using Linux to perform the various steps.
Note: The parted and mkpart steps are partitioning the hard drive properly for the structure used by the My Cloud OS3 firmware. One (assuming they haven’t corrupted one of the existing partitions) can bypass those steps and the mkswap and mkfs.ext4 steps if one want to try and keep the user data intact on the hard drive.
I tried the alternative way (didn’t notice it before).
Unfortunately, it didn’t work either. The only way now to know what is happening on the board is through serial connection which I don’t have the tools or knowledge of. So, I decided to give up on this and ordered a diskless WMC Ex2 Ultra.
Updating to Cloud OS 5 before reading feedback was a mistake. This indexing thing they implemented nearly fried my system and now it is dead. Good thing the drive is still alive.