Obviously something is still wrong with how you setup the drive. Below are the URL’s (from what I remember) that I used when setting up an old 250GB drive in a WD My Cloud enclosure.
One word of note, do not format or partition the drive as it was a 250GB drive, instead follow the directions exactly for partitioning and drive sizing. This is what I used, from the google drive link above:
mkpart primary 528M 2576M
mkpart primary 2576M 4624M
mkpart primary 16M 528M
mkpart primary 4828M -1M
mkpart primary 4624M 4724M
mkpart primary 4724M 4824M
mkpart primary 4824M 4826M
mkpart primary 4826M 4828M
Make sure to perform the steps exactly when it comes to setting up the RAID.
I cannot remember if I pushed just the “rootfs.img” to the drive or if I pushed both the “rootfs.img”, “config.img” and “kernel.img” to the drive using DD. But I do remember pulling down the latest firmware for the WD My Cloud from this WD Support link and using the “rootfs.img” file from it. I thought I read somewhere, back when I did my drive at the beginning of this year, in one of the many unbrick threads that it was possible to restore a drive simply by pushing the “rootfs.img” file. But I could be wrong as I cannot seem to find that post again.
I used a Linux OS boot CD to boot a desktop PC and performed all the commands from within Linux. I did not use an external enclosure, rather used a desktop PC and connected the 250GB drive to one of the internal SATA and power cables. I did disconnect all other drives from that desktop to prevent inadvertent overwriting of other drives.
It took me several tries with the various directions because I missed a step or typed in a command wrong before it finally worked.