It's something you can do since a lot of years. I used to do so 10 years ago, when I've got the first motherboard with UEFI. But is it useful? It saves a minimal time in the boot sequence, but at what cost?
The bootloader (being it grub, or something more simple as systemd-boot) is useful to me for a couple of reasons:
- it allows to dual-boot with Windows easily: motherboard boot menu is often not easy to access, you need to perform some key combination in a short window, also modern bootloader save the last boot option such that if Windows reboots for an update Linux does not start
- it allows to edit the cmdline of the kernel to recover a system that does not boot, e.g. start in single user mode. That can really save your day if you don't have on hand an USB stick and another PC to flash it
- it allows you to choose between multiple kernels and initrd images easily, again for recovery purposes
- it has a voice for entering the UEFI setup menu: in most modern systems again entering the UEFI with a keyboard combination is unnecessarily difficult and has a too short timeout
- it allows you to boot any other EFI application, such as memtest, or efi shell. Most UEFI firmwares doesn't have a menu to do so.
The bootloader (being it grub, or something more simple as systemd-boot) is useful to me for a couple of reasons:
- it allows to dual-boot with Windows easily: motherboard boot menu is often not easy to access, you need to perform some key combination in a short window, also modern bootloader save the last boot option such that if Windows reboots for an update Linux does not start
- it allows to edit the cmdline of the kernel to recover a system that does not boot, e.g. start in single user mode. That can really save your day if you don't have on hand an USB stick and another PC to flash it
- it allows you to choose between multiple kernels and initrd images easily, again for recovery purposes
- it has a voice for entering the UEFI setup menu: in most modern systems again entering the UEFI with a keyboard combination is unnecessarily difficult and has a too short timeout
- it allows you to boot any other EFI application, such as memtest, or efi shell. Most UEFI firmwares doesn't have a menu to do so.