Howto make a legacy bios/uefi dual boot usb stick with grub2

[aus9]

Hi Juanito

Internal server error so have altered  and split post
AND for hecks sake just move to linuxquestions this is a joke the number of times I have an internal server error
My test PC is a new laptop with Windows 11 pre-installed
bios/uefi settings:
- disabled fast boot & secure boot
- unable to disable uefi
- boot order changed to boot usb before emmc
- emmc means my first detected device (usb) gets /dev/sda* formats


1) Your dual bios legacy/uefi has a misleading line in it

search --no-floppy --fs-uuid --set=root d4432cde-d21a-4d40-b44b-f097ce72cdba

The reason this should be deleted, IMHO is that you are telling grub where to find the balance of
grub's booting files  ie sdc1

But that was decided by your grub-install commands BEFORE you instructed to create grub.cfg

[aus9]

still more internal server errors....I am not angry ?

cd /mnt/sdb2/EFI/
ls
BOOT/          corepure64.gz  vmlinuz64

[aus9]

grub.cfg
top section
loadfont unicode
insmod all_video
set gfxmode=800x600
set gfxterm_font=unicode
terminal_output gfxterm
set timeout=5
set menu_color_normal=cyan/blue
set menu_color_highlight=white/blue

[aus9]

grub.cfg menu section due to you know what forum errors

menuentry "TC64" {
linux /EFI/vmlinuz64 home=sda1 tce=sda1 waitusb=10:sda1 quiet
initrd /EFI/corepure64.gz
}


I accept that you have attempted to do both legacy and uefi, while I am selfishly doing only uefi

I suggest that anyone who has time......delete the line I allude to and reboot and see if you still boot.
It works for me and good luck

[aus9]

I made an error in my comments by pm link on tcedir. ignore them please

I now realize that the line that is misleading is pointing to sdc1 when if it ever had a chance to work....it should have pointed to sdc2,
where your grub.cfg lies

[patrikg]

When posting code of something like grub config, you can test to use the code button "#".