There are numerous free Linux distro’s available. I wound up using Ubuntu but there are others that might be better or easier to use.
https://www.ubuntu.com/download/desktop
That link (at the bottom) has further links on how to create boot DVD/USB media. One can either boot their PC with that media or actually install Ubuntu to a portion of their hard drive (or other location). I ended up installing Ubuntu to a portion of a Windows 10 boot drive but not everyone will want to do that.
The main problem I’ve found with all of the various instructions is one ends up having to create their own custom set of directions as they work through the process since commands may be different across different versions of Linux. Here are a couple of examples that show why one may end up having a custom set of directions and why a generic set (while useful as a guidline) may not work for everyone.
For the recent older 1TB Seagate Barracuda drive I unbricked earlier this week, I used the Fox_exe 1st gen directions: https://drive.google.com/file/d/0B_6OlQ_H0PxVbzZac0plbkZKeGM/view
I ran into problems with the hard drive I was using throwing superblock and GPT errors for some reason (I’ve had this problem with other drives I’ve unbricked for a first gen My Cloud). So I had to (if I remember right) run gdisk from the Ubuntu terminal command line, then select r, then f, then w which wrote the fixes to the drive. Then I could start with the Fox_exe directions. I restarted the hard drive drive after doing the parted steps. I leave out sudo mdadm -A /dev/md0 /dev/sdb1 /dev/sdb2" on step 8 otherwise I get errors when attempting to do “sudo mdadm --create /dev/md0 --level=1 --metadata=0.9 --raid-devices=2 /dev/sdb1 /dev/sdb2”.
If I use the v4.01.02-417 set of img files I get an out of space error when when running the “sudo dd if=kernel.img of=/dev/sdb5” command. So what I’ve been doing is using the v3.04.01-230 set of img files, then downloading the actual v4.01.02-417 WD firmware from WD and updating it at a later point, then download the latest firmware from WD and update from v4.01.02-417 to v04.05.00-334 WD firmware.
After reattaching the My Cloud plate/motherboard to the unbricked hard drive and booting it, it took a while (10 or so minutes) for the front LED to change a green or yellow to red. Happens every time, LED turns red rather than blue. I then open up a web browser and access the My cloud Dashboard (http://wdmycloud or http://wdmycloud.local) and issue a Quick Restore from the Dashboard > Settings > Utilities page and that seems to fix the content mount issue causing the red LED at boot.
After rebooting and getting a blue front LED I then upgrade to the latest firmware by first upgrading from v3.04.01-230 to v4.01.02-417 then to the latest firmware v04.05.00-334. Don’t know if one can jump from the v3.x firmware to the very latest version. Haven’t tried it. May next time I do an unbrick.
Others may not have my issues or need to do the various things I do. For me the above general steps seems to work most of the time.
