TerraMaster Forum

So, based on numerous other forum entries, the device is bricked, but the HHDs appear to be okay. I have attempted to access the data using Linux, but I am not very good at using Linux, and so far, no dice.

I can use the TNAS PC program to locate the F2-221 on the network, but it prompts me to "initialize" (short for delete all your data) and reinstall TOS. I, of course, do not wish to delete all of my data, so I have removed the 2 8TB drives and inserted a 4TB drive that I had been using until about 3-4 months ago. I go through the TOS Initialization process. I have tried both standard and custom installation options (Custom seems to do a disk check, and it passes with no problem), but then it fails, and I receive an error message at approx 93% of the TOS installation. It asks me to restart the device and try again - which I have not done now countless times.
I have removed the case and tried removing the battery and power cables (and HDD) - even let it sit overnight once. I still cannot install TOS.
At this point, I am wondering if I should hire a Linux expert to find and retrieve my data and then buy a new NAS or...

All HHDs (2 x 4TB and 2 x 8 TB are Seagate IronWolf and work fine. Raid was set to RAID1 (so, each drive should, in theory, mirror the other one, right?) Both HDD Lights were green a few weeks ago when I last looked at the device before it stopped working. Now, both HDD lights are red. When turned on, the Power light is Green, and when connected to the network, the LAN light flashes green.

Any and all input would be appreciated.
Thanks!

If you didn't encrypt your folders, then obtain something like Parted Magic to load into its live environment to access your data on your drives which aren't loading into TOS; if you aren't comfortable doing this, maybe consult a friend who comprehends Linux more than yourself to assist.

If the installation is failing near the end (>90%), that's possibly a UEFI/BIOS or hardware incompatibility, which is one of the reasons the newer TOS 6.× builds are no longer supported on the 221 & 421 series TNAS devices.

Based on your description, it appears that your TNAS hardware is not damaged, as it boots up normally and your TNAS PC is able to detect the device. The inability of TOS to start up properly may be due to a corrupted system partition on the hard drive, which could be caused by either a damaged hard drive or a corrupted file system—I cannot be certain. From my deduction, your 4TB hard drive may have some errors. You might want to try formatting this 4TB drive and then reinstalling the system. If the issue persists, you should then attempt using a different hard drive.