Slackware 15.0 not booting after a CMOS battery change - how we fixed it
by KGHN from LinuxQuestions.org on (#6HC4S)
Slackware 15.0 elilo machine was not booting after a CMOS battery change. "No boot device available" It was booting to Slackware before the battery change. (We changed the battery because it keeps losing the time's hour whenever it's shut down and restarted, but keeps the minute - it still does, and the old battery seems fine.)
BIOS Setup could see the SSD (sda, where the boot files were on sda1) and the HD sdb.
Slackware 15 could be launched as an available option once the installation DVD was booted.
Research found efibootmgr utility plausible to help, but there's only a Slack package for 14, not 15.
We booted the installed Slackware via the installation DVD, and found that our Slackware 15.0 installation has efibootmgr available, but only to root use. "not found" to normal user. So, as root,
efibootmgr
command shows DVD, UEFI DVD, and the drives, no "Slackware".
We followed instructions to create an EFI boot entry:
Step 1 of 2: We copied elilo-x86_64.efi from /boot to /boot/efi/EFI/Slackware directory, as there was no *.efi file in that directory.
Then, step 2 of 2:
efibootmgr --create --disk=/dev/sda --part=1 --label="Slackware" --loader='EFI\Slackware\elilo-x86_64.efi'
This created an EFI boot entry and set it as the default boot. ...Thank you for super help,
https://linuxconfig.org/how-to-manag...tries-on-linux
It boots, hooray! (Machines with support for the UEFI firmware stores boot entries in the non-volatile RAM called NVRAM, which needs continuous CMOS battery power to remember. Poor thing had forgotten which drive and partition was bootable.)
It took me a good while to research and solve this, so I'm posting hoping to help another Slackware fan through their research.
BIOS Setup could see the SSD (sda, where the boot files were on sda1) and the HD sdb.
Slackware 15 could be launched as an available option once the installation DVD was booted.
Research found efibootmgr utility plausible to help, but there's only a Slack package for 14, not 15.
We booted the installed Slackware via the installation DVD, and found that our Slackware 15.0 installation has efibootmgr available, but only to root use. "not found" to normal user. So, as root,
efibootmgr
command shows DVD, UEFI DVD, and the drives, no "Slackware".
We followed instructions to create an EFI boot entry:
Step 1 of 2: We copied elilo-x86_64.efi from /boot to /boot/efi/EFI/Slackware directory, as there was no *.efi file in that directory.
Then, step 2 of 2:
efibootmgr --create --disk=/dev/sda --part=1 --label="Slackware" --loader='EFI\Slackware\elilo-x86_64.efi'
This created an EFI boot entry and set it as the default boot. ...Thank you for super help,
https://linuxconfig.org/how-to-manag...tries-on-linux
It boots, hooray! (Machines with support for the UEFI firmware stores boot entries in the non-volatile RAM called NVRAM, which needs continuous CMOS battery power to remember. Poor thing had forgotten which drive and partition was bootable.)
It took me a good while to research and solve this, so I'm posting hoping to help another Slackware fan through their research.