While i have done this unbricking in the past, about 2 years ago.
Im tyring the same thing today. However after unbricking with the backup firmware and then upgrading to 4.x firmware. Im losing the dashboard. I’ve already tried teh “gdisk” to correct the GPT. I recall this did work two years ago.
Any clues what could be going on. Im basically replacing the disk in my wdmycloud.