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I have dual boot Ubuntu/Windows 10 on my Acer laptop. UEFI system. I've just figured out that when I simply enter the BIOS settings by pressing F2 at start (without changing or saving anything), or also when entering the BOOT MENU settings by pressing F12 at start, then GRUB permanently disappears and instead Windows 10 loads. After this, GRUB must be reinstalled from a Live CD or by reinstalling Ubuntu from scratch.

How is this possible???

Sumeet Deshmukh
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W.Roger
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  • The only thing i can imagine is that you have a problem with buggy firmware. Try to update UEFI/BIOS to latest version if available. – mook765 Apr 23 '17 at 09:18
  • I already updated the BIOS to the latest version, before installing Ubuntu. – W.Roger Apr 23 '17 at 09:24
  • Contact Acer support at https://www.acer.com/ – mook765 Apr 23 '17 at 09:57
  • When you exit are you resetting to defaults? Acer requires you to enable supervisory password & set trust on the grub/ubuntu .efi boot files. You may be losing those entries as it reverts to defaults. Acer Aspire E15 will not dual boot, many details Trust settings in step 35 http://askubuntu.com/questions/627416/acer-aspire-e15-will-not-dual-boot – oldfred Apr 24 '17 at 16:13

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This sounds like buggy firmware. Check for an update on Acer's site. (It will probably be called a "BIOS update" or something similar, although if the computer was sold any times since late 2011, it's more likely to be an EFI/UEFI than a BIOS.)

If there's no firmware update, or if applying it doesn't help, then you should complain -- loudly -- to Acer, since this is a serious bug. Beyond complaining, there are better workarounds than what you're using:

  • fbx64.efi -- Recently, Ubuntu has begun shipping this EFI program file and installing it in /boot/efi/EFI/ubuntu (from Ubuntu). I have yet to study this file in detail, but it's intended to work around the sort of problem you're describing. To work automatically, you'd probably want to copy it to /boot/efi/EFI/bootx64.efi (from Ubuntu), but it may require explicit configuration beyond that, and I haven't yet looked into that detail. Also, this might not really do anything by itself if your computer boots straight to Windows. Thus, you might want to focus on the next solution....
  • Fix the boot entries -- One or both of two NVRAM-based EFI settings are being changed: The BootOrder variable holds the boot order, and Boot#### entries (where #### is a hexadecimal value) hold pointers to specific boot loaders. If the BootOrder alone is being changed, you can fix it with various tools, like efibootmgr in Ubuntu or bcdedit in Windows. Since you're booting straight to Windows after such an incident, the easiest fix is likely to be to use the third-party EasyUEFI tool, which enables you to adjust the BootOrder variable in a simple GUI list. Even if the Boot#### entry for Ubuntu is being deleted, you can use EasyUEFI or bcdedit to create a new entry that points to EFI\ubuntu\shimx64.efi. Typing bcdedit /set {bootmgr} "\EFI\ubuntu\shimx64.efi" in an Administrator Command Prompt window should fix the problem with bcdedit; or you can do the equivalent in EasyUEFI.

This is just one example of what I call a boot coup. See this page of mine for more on this subject. (That page is part of my rEFInd documentation, but the principles apply to other boot loaders.)

Rod Smith
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