GRUB does not support NVMe devices
Non-volatile memory NVM Express (NVMe) devices are not supported by the
GRUB boot loader in Red Hat Enterprise Linux 6, and therefore the boot loader can't be installed on these devices.
To work around the problem, you can:
Use another storage device to install the boot loader
Upgrade to RHEL 7, which uses
GRUB2 as the default boot loader and supports installation to NVMe devices
GRUB updates are not applied to the system
GRUB boot loader is updated using
rpm (for example,
rpm -Uvh grub), and the update process succeeds, then the
grub-install command is not being run automatically due to technical limitations of
GRUB. The updated package is downloaded and installed, but the new version of the boot loader provided by that package is not automatically applied to the system. Instead, the old version is used even after the package update, and therefore any fixes provided in the update are not applied to the system.
To work around this problem, run the
command manually using a command line with
privileges every time an update to the grub
package is installed. (BZ#1573121
GRUB Legacy does not support SHA-encrypted passwords
In UEFI mode,
GRUB Legacy supports only MD5-encrypted passwords and does not support SHA256 and SHA512-encrypted passwords. Consequently, the operating system becomes unresponsive at boot time, when using SHA256 and SHA512-encrypted passwords in UEFI mode.
To work around this problem, you can: