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Boot Order Unexpectantly Changed (dRENTFS)

Level 7
Powered up this morning, and was suddenly faced with a screen that just said dRENTFS (actually the d was a delta, and the E had an accent over it). Boot code on the motherboard was AE (Boot Legacy Event)

Turned out the boot order had changed on the Bios (I have two drives). Surely the BIOS is supposed to remember this?
What is odd, is that when you exit the bios and save changes, it gives you a list of all the changes, only the change to the boot order is not one of them.

I can only guess that the default is to set the boot order with the lowest port ID first, whereas my boot drive is the last one. I am only guessing, but perhaps you are supposed to plug your boot drive into the lowest ID port?

Thought I'd post, just in case someone else ever had the same issue (Googling dRENTFS didn't really return many results)

Level 13
Normally, boot order is determined in BIOS on the fly and can change any time a difference in boot sources is detected. To try this, boot into BIOS with a USB drive plugged in - it will show up in the boot order. Which one is first is by logical preference: UEFI boot file first if found on any drive, then the drives. You can disable unwanted choices and reorder them in BIOS and those will be remembered until BIOS detects a change in the drives.

When booting goes wrong like that, check the SATA and power connections to drives. Are the drives spinning during POST?

That display code is strange and looks like garbage. I suggest clearing CMOS - see the manual for whether your motherboard model uses a button or a jumper. You will have to apply settings or a profile again.

If that doesn't fix booting, and the drives appear to be working, perhaps BIOS needs to be re-flashed.


Clearing CMOS was one of the first things I did. The two drives are both SSDs. Motherboard is M7F.
My best guess as to what happened is that for some strange reason the first one took too long to respond, and so the BIOS then moved onto the second one, which has no O/S loaded (but is not empty). After a reboot, the 1st drive comes back (so appears when you examine the BIOS), but it is added back in 2nd place.
The BIOS has two lists, one which sets the order between optical discs, and hard drives, and one for the hard drives them selves. It is this second one that I had to reorder to solve the problem (and therefore this one that I assume the BIOS altered).

Level 10
When you set the boot bbs drive priority list and then come back up to the boot order list it shouldn't change after you set and save it. If your disappearing drive is a ssd then I'd run the manufactures utility on it and make sure that it checks out okay.
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Level 13
There is a BIOS adjustment that can help in cases where some drives come and go intermittently.

Extreme Tweaker tab > Tweaker's Paradise > Sata Drive Strength

Increasing or decreasing that may make for more consistent booting. Take the adjustment in steps of +/- 1. Don't go too far, or some other drive may start misbehaving. This helped me with an optical drive that worked about half the time.