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RAID 1 (mirror) based on Intel RST ROM broken after BIOS battery discharge


Hi All!

I had a 10-year old ASUS P7P55D MoBo with enabled built-it RAID 1 (mirror) based on Intel RST ROM.


Everything was fine till few weeks ago my BIOS battery was completely discharged and I had to replace it.

Obviously all BIOS settings were erased including RAID but I didn't realize that till today 8-(


So today I had:


- windows 10 booting to (third, non-RAID-ever SSD drive)

- one of former RAID-disks online

- second - not mounted with error in Disk Devices (GUID duplicate or smth similar)


I tried:

- switch BIOS back from IDE to RAID disk mode 

- enter RST ROM UI (Ctrl+I) - and no disks are in RAID anymore, no option to recover or I can't see those

- windows 10 can't boot to (third, non-RAID-ever SSD drive) in RAID mode anymore (blue screen with sad smile :() while it was booting successfully before battery fault


Now I switched BIOS back to IDE:

- windows 10 can boot now

- both former RAID-disks are online, with separate drive letters assigned. Last file on 'offline' drive obviously is several weeks old



1) Can I repair/rebuild the RAID 1 (mirror) from those disks without data lost? And make Win10 boot with RAID mode turned on again?



2) Hot ot prevent same accidents in future? 

Need backup for BIOS backup battery ;)



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1 Reply
Super User
  1. The BIOS configuration is stored in flash, not CMOS, so all you lose if the battery fails is the date and time. Specifically, the settings ARE NOT erased by a battery failure. Something else (likely you loading BIOS Defaults) caused you to lose the configuration.
  2. The drive is offline because if is a duplicate of the first drive (from mirroring).
  3. If you want to use RAID, then you need to install Windows with RAID enabled.
  4. Make a backup of the data on the first drive before changing over to RAID. Better safe than sorry.


Hope this helps,


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