I’m trying to make more room for rootfs since, with every growing system requirements, it is now too small. I booted to live image and made two copies of current rootfs on two spare partitions. Once with dd the other with cp -a . This system did not have separate /boot so all three have a complete bootable image. I also made clone of /boot on a small 4GB partition since I would prefer to separate it anyway.
The dd clone had a identical UUID so I changes one of them to avoid confusion.
I’m having difficulty getting to boot to either of the new fs partitions.
One of key config lines in /boot/grub2/grub.cfg it setting grub’s “root”. This means it already has to know which partition has the required /boot/grub2/grub.cfg
By deduction I’m guessing that this is set by grub2-install and must be hard coded into the bootloader in the MBR ( this is a BIOS system not effing EFI ) . Presumably it just assumes that you want to carry on with the same installed fs so it just comes back to the old rootfs.
man grub2-install does not seem to provide any means of setting a new “root” for grub.
How can I get it to look at the new boot partition ( /dev/sda2 ) where I can then set it to use the new rootfs ?