Saturday 25 April 2020

How to fix the issue of the BIOS not listing an MBR\Legacy boot option to boot to the E2B menu

If your E2B USB drive now has a FAT32 partition with UEFI boot files in the \EFI boot folder, you may find that some systems will not offer you the choice to Legacy from your E2B USB drive (even though you have enabled CSM) - the only option is to UEFI-boot (or set the BIOS options to disable UEFI-booting) which may not be what you want to do on some occasions. You may need to run a Legacy payload using E2B.

Where is the Legacy boot option?
These buggy BIOSes do not present a Legacy-boot (unless you can change the BIOS options to disable UEFI-booting which sometimes is not possible).

We can however rename the \EFI folder on the 2nd FAT32 agFM partition and this will cause the BIOS pop-up boot menu to list the Legacy-boot option.

Of course this means you won't be able to UEFI-boot from the E2B drive until you rename the folder back to "\EFI" again.

agFM v1.45 contains an agFM Disable or Enable UEFI booting.cfg file in the root which allows you to quickly rename the \EFI folder and so disable UEFI-booting. There is also a new startup menu entry too. You can then reboot to the Easy2Boot menu system.

Default agFM menu

In agFM file manager - select the .cfg file in the root of the agFM partition
Easy2Boot v2.03b contains a sample .mnu file which will allow you to rename it back again to \EFI.

Copy the .mnu file "\_ISO\docs\Sample mnu files\E2B Menus\Enable or Disable UEFI booting.mnu" to the \_ISO\MAINMENU folder so it shows in the Main menu...

Use this E2B menu option to enable (or disable) UEFI-booting.

Instead of using this E2B .mnu file, you can MBR-boot to the agFM menu (menu item 2 in the screenshot above) and then use the agFM .cfg file.

P.S. The new version of eBook #4 was updated this morning.

Tip: You can add the agFM .cfg file as an entry into your agFM Startup menu if you wish to make it easier to find.

Required files

PTN1: \_ISO\docs\Sample mnu files\E2B Menus\Enable or Disable UEFI booting.mnu
PTN2: \Disable or Enable UEFI booting.cfg 

PTN1: \_ISO\MAINMENU\a1ive grub2 filemanager.mnu  (to boot to agFM from the E2B menu)

No comments:

Post a Comment