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Updated grub packages that fix several bugs and add one enhancement are now available for Red Hat Enterprise Linux 6.
The grub packages provide GRUB (Grand Unified Boot Loader), a boot loader capable of booting a wide variety of operating systems.
- If the title of the GRUB menu entry exceeded the line length of 80 characters, the text showing the remaining time to a boot was inconsistent and thus appeared to be incorrect. The overflowing text was displayed on a new line and the whole text was moved one line down with every passing second. This update splits the text into two lines, and only the second line is rewritten as a boot countdown proceeds so that GRUB behaves correctly for long menu entries.
- When building a new version of grub packages, GRUB did not remove the grub.info file upon the "make clean" command. As a consequence, the grub.info file did not contain the latest changes after applying an update. To fix this problem, the GRUB Makefile has been modified so the grub.info file is now explicitly removed and generated with every package build.
- The GRUB code did not comply with the Unified Extensible Firmware Interface (UEFI) specification and did not disable an EFI platform's watchdog timer as is required by the specification. Consequently, the system was rebooted if the watchdog was not disabled within 5-minutes time frame, which is undesirable behavior. A patch has been applied that disables the EFI watchdog immediately after GRUB is initialized so that EFI systems are no longer restarted unexpectedly.
- When booting a system in QEMU KVM with Open Virtual Machine Firmware (OVMF) BIOS, GRUB was not able to recognize virtio block devices, and the booting process exited to the GRUB shell. This happened because GRUB did not correctly tested paths to EFI devices. The GRUB code now verifies EFI device paths against EFI PCI device paths, and recognizes disk devices as expected in this scenario.
- GRUB did not comply with the UEFI specification when handling the ExitBootServices() EFI function. If ExitBootServices() failed while retrieving a memory map, GRUB exited immediately instead of repeating the attempt. With this update, GRUB retries to obtain a memory map 5 times before exiting, and boot process continues on success.
- When building a 64-bit version of GRUB from a source package, it fails to link executable during the configure phase, unless a 32-bit version of the glibc-static package is installed. No error message was displayed upon GRUB failure in this situation. This has been fixed by setting the grub packages to depend directly on the /usr/lib/libc.a file, which can be provided in different environments. If the file is missing when building the grub packages, an appropriate error message is displayed.
- When installed on a multipath device, GRUB was unreadable and the system was unable to boot. This happened due to a bug in a regular expression used to match devices, and because the grub-install command could not resolve symbolic links to obtain device statistics. This update fixes these problems so that GRUB now boots as expected when installed on a multipath device.
- When booting in UEFI mode, GRUB previously allocated memory for a pointer to a structure instead allocating memory for the structure. This rendered GRUB to be unable to finish and pass control to the kernel on specific hardware configurations. This update fixes this problem so GRUB now allocates memory for a structure as expected and successfully passes control to the kernel.
- Previously, GRUB could not be installed on Non-Volatile Memory Express (NVMe) devices because it was unable to parse a device name during the installation process. This update adds a regular expression support for matching NVMe devices, and GRUB can now be successfully installed on these devices.
- GRUB now provides a new menu option "macappend". When "macappend" is used either in the grub.conf file or on the GRUB command line, the "BOOTIF=<MAC_address>" parameter is appended to the kernel command line. This allows specifying a network interface for Anaconda to use during a PXE boot.
Users of grub are advised to upgrade to these updated packages, which fix these bugs and add this enhancement.