There's a certain order of operations needed to get a drive unraided, and it's all a bit weird, but basically I need the SATA ports to be AHCI rather than RAID.
I half-did the job using the F11 EZ config tool in the Asus BIOS, but that was a mistake! It half-made a RAID using two of the three drives, but then no drives would show up in boot. Turns out I should just use the ‘proper’ (i.e. not EZ) Intel RAID tool.
I've just used it to make a whole new RAID of all three drives (because two drives were ‘trapped’ in that old weird RAID) and will now delete that RAID which should hopefully ‘free’ all the drives…
…and it didn't work: two drives are still trapped, weirldy still with the old name I gave the three-drive RAID (RotLA, obvs). More research needed.
AND I can't install windows on the SSD; probably still something to do with SATA being RAID configured…
Ok, changing back to AHCI allowed Windows to say it can be installed, but that two-drive RAID is still there…
Trying another three-drive RAID, but making it RAID1 (mirror) instead of the RAID0 (stripe; basically just butted up to each other). This might help by giving the drives a proper ‘nudge’ into a totally different mode…
Correction: trying RAID5. RAID1 is only to mirror two drives max.
Back in the Windows installation, it won't let me install on any drive because RAID not AHCI.
TIP: in Asus BIOS, turning Intel Rapid Storage Technology RST on & off is done in EZ Mode (note: this not the same EZ as mentioned earlier!) but actually configuring anything is done in “Advanced” mode.
Weird: simply turning off RST gives the same old drive config showing up at install.
(Zarking hell, this is a lot of pissing about. If this gets sorted, I don't think I'll bother with RAID ever again; just make more back-up.)
Yikes, still not showing three separate drives. Time to start physically unplugging them…
(Yikes, case has evidence of previous spider nesting inside: lots of tiny moulted exoskeletons.)
Just leaving the SSD in didn't help: Windows still refuses to install on it.
Next plan (after a looooong diversion to fix a power button issue) is to plug the drives into a another computer one by one via USB thingie and see what we can do.
Interesting! One of the drives from the old RAID plugged in on its own is recognised by Windows as belonging to a pool and even shows that there were originally three in the pool and the old RotLA name. It even gives me the option to “Delete pool”. Ha ha, guess I'll deffo be trying that, having run out of other options!
https://aidanfinn.com/?p=16571
…But the FriendlyName is NOT RotLA for some reason!
Used Get-StoragePool to list pools and find the name is actually just “Storage pool” (roll eyes emoji…)
Failed on the first go, but seemed to work on the second try…
(NB: Letter Case Matters For PowerShell Commands!)
2319
All done! By plugging all four drives (three storage + SSD system disk that EZ RST nonsense wiped) in individually via USB to another computer and using PowerShell & CaFHDP to wipe and format, they're all rescued and Windows 10 IoT is installing.