HP PC does not boot Linux Manjaro (3F0) BootDevice Not Found, EFI/GPT/MBR/LUKS issue?

Hello, i want to ask you for help with Manjaro on new 2020 Hewlett Packard computer into which i have placed Manjaro system drive that i have removed from my other computer (which has Legacy boot, IDE). In this new PC is no Legacy boot BIOS option and makes an impression on various screens that it is using EFI. I only disabled secure boot (suggested to work only with Windows) and fast boot. Boot priority is right.
But this computer does not boot the drive:
HP 3F0 Boot Device Not Found - IDE LUKS Manjaro Linux drive
even the drive is OK and passes the diagnostic tests made in this new PC.
Manjaro live & Hiren boot CD boots OK from USB stick.

If i can not disable EFI (if that is what prevents booting) in BIOS, what is the workaround to boot from this system drive which is full LUKS encrypted (except grub boot?), i read that maybe GPT/MBR can be the cause or maybe lack of EFI(UEFI) support in boot area of the drive. Maybe i can either run some boot manager that can help in booting or i can create €FI part. on an external drive to link to my LUKS drive?

kernel parameters (found in grub-customizer utility):

cryptdevice=UUID=abc:luks-abc root=/dev/mapper/luks-abc apparmor=1 security=apparmor udev.log_priority=3

My grub boot entries are here please appears like if boot partition is ext2 msdos luks, i see no efi. fallback initrd line does not have /boot/amd-ucode.img while new PC is AMD Renoir.

sudo gdisk -l /dev/sda” says “Found invalid GPT and valid MBR”. This is single OS drive.
test -d /sys/firmware/efi && echo UEFI || echo BIOS” says “BIOS”
sudo efibootmgr -v” says “EFI variables are not supported on this system.”

Thank you in advance

UPDATE: the solution may be
A) complicated, rather for geeks: to boot live Linux usb system, use gparted tool to resize decrypted LUKS fs, then LUKS itself, then partition and then create new 300MB FAT32 partition with boot and esp flags (/efi or /boot/efi), does not matter if part is at the end of drive). I think there are guides for this. Then you would have to install efi things, rebuild the grub and hope all will go right.
B) easier one: install new system and copy the data over, easiest would be to copy /home/username contents and then isntall same apps:

Old PC: pacman -Qqen > pkglist.txt;pacman -Qqem > pkglist_aur.txt
New PC: pacman -S --needed - < pkglist.txt; for p in $(cat pkglist_aur.txt);do pamac build $p --no-confirm;done
or rsyncing nearly everything (can be tricky to choose right rsync switches) and may be important to run on old running system (not on live USB))

sudo mount --bind / /mnt
sudo rsync -av --progress --sparse --links --hard-links /mnt/ sshuser@sshserver:/

you are doing above things on your risk, after having backup on separate drive.

see this

would this make it better? i use manjaro with legacy boot enabled and im running just fine i use an HP pavillion 17 g121wm. no problems at all

After more research (1!, 2) i think that it is likely that these new computers will no longer support legacy BIOS/CSM, 32bit, MBR.

These possibly support only EFI and GPT, so i guess focus should be on how to convert current system to be EFI and GPT.


Though i am unsure if i should follow that commands exactly as mentioned, especially:

sudo grub-install --target=x86_64-efi --efi-directory=/boot/efi --bootloader-id=manjaro --recheck

is correct and how to properly:

create an ESP (EFI System Partition).

It is a FAT32 partition which has the .efi files for booting, which you can create using Gparted or gdisk. (Size 200-512 MiB).

Update: i have updated first post of this topic