The GRand Unified Bootloader (Grub) is one of the best known free boot loaders. Once developed as a replacement for LILO in the context of the GNU Hurd project, now hardly a distribution comes without him. Because the modular boot loader supports a number of platforms and offers functions that are searched for in other systems in vain. Among other things, Grub can access the operating system cores stored as files via the file system. In contrast to other bootloaders, Grub does not need to know the exact location of the files – however, one prerequisite is that Grub masters the file system itself. For this purpose, the developers have gradually expanded the loader with support for new file systems, so that Grub should also be able to cope with new functions of current platforms.
With the now released first release candidate, the developers behind the boot loader have ushered in the final phase of the development of Grub 2.04 two years after the last release. After Grub has dealt with Btrfs partitions for over seven years, the developers have further expanded the loader. Among other things, the new version supports the compression using Zstd as well as RAID5 and RAID6. In addition, Grub now comes with the F2FS file system and is able to load various pre-images of Initrd before the actual start of the system. The change results from an attempt to start an alternate code before starting a system, for example, to fix bugs in an architecture in advance.
Platform support has been further developed and existing platforms have been improved. New features include support for RISC V systems and improved support for Xen. The support for UEFI systems was further expanded and Grub extended, among other things, with a new framework for UEFI Secure Boot and UEFI TPM. Furthermore, the framework can also be used by external modules, so that, for example, Grub himself can verify his signature by means of PGP. A list of other changes can be found in the changelog.
Submitted by: Arnfried Walbrecht