Upgrade RHEL from 7.9 to 8.8 to avoid GRUB corruption

Directly upgrading from RHEL 7.9 to 8.10 may corrupt GRUB and prevent the system from booting. To avoid this, perform an intermediate upgrade to RHEL 8.8 first.

Steps

  1. Enable required RHEL 7 repositories to install the upgrade utility.
  2. Install the leapp package to perform the OS upgrade.
  3. Run leapp preupgrade targeting RHEL 8.8 to detect any upgrade blockers.
  4. Unload the pata_acpi kernel module if required to proceed.
  5. Provide confirmation for removing unsupported PAM modules in the answerfile.
  6. Execute the upgrade using leapp upgrade --target=8.8.
  7. Reboot the system to apply changes and complete the upgrade to RHEL 8.8.