I have Windows 11 on an M2 and Fedora Linux on a regular SSD. I don’t use GRUB, I always select the system via Bios. It’s my preference to do it this way. Today when turning on my Acer laptop (Model A515-54, series 5577, V.1.24 made in Brazil), the system started on Linux, although I am very sure that I turned it off on Windows last night. How is this possible? I’ve never seen the Bios change the main disk itself.

I’ve been using computers since 1993 and I’ve never seen BIOS/UEFI change the boot order without user intervention. I was very intrigued by this “disc” change. Detail: I have a password set for Bios access and the system clock has not been delayed recently (I don’t think it’s a low battery situation).The Windows drive has Bitlocker enabled and the Linux drive is also encrypted. The laptop was without the power cable and without the RJ45 network cable plugged in during the night, so it wasn’t a “wake up on lan” type of thing. A true mystery. What could have caused this?