I thought it would be simple. My old boot partition was /dev/sda1. My new boot partition is now /dev/sda7 (using MBR). Unfortunately when I reboot, it still goes to the old boot partition to get the kernel defined there. I look at some of the grub stuff and the configuration still says that it uses “msdos1”. Of course when everything is booted, /etc/fstab mounts the new boot partition. I am obviously missing something. I’d rather not fool around with gparted, or similar tools. Obviously when dnf brings in a new kernel, the bootable stuff (initrd, kernel) are all put in the new (mounted) boot partition. Any clues?
I don’t use MBR myself, but I suspect you might need to reinstall grub into the MBR to pick up the changes:
grub2-install /dev/sda
Reference: Fedora docs
Yes, I thought so as well. It didn’t work. I must need to change some configuration somewhere, but I have yet to figure out what.
I manage to change my old boot to new one,Firstly I make new boot and copy files from old one .
After that you can see I add flags to new boot – boot,esp and old one to no_automount
Once I did that I add new boot uuid to fstab and uncomment old one save it and reboot
You can see new boot is mounted
I hope this will give you some idea how to do it
The boot,esp flag should only be set on the ESP partition which should be formatted as vfat and mounted on /boot/efi. For systems which doesn’t boot in UEFI mode you don’t need an ESP partition.
Ok ,thanks good to know 
and that mean don’t flag new boot to boot,esp @sdc695 please
All of suggestions look nice, but when using MBR style partitions they don’t seem to work. Could it be because the new boot partition is not a primary partition? Or is because of some old limitation not being in the first xxxMb of the disk? It seems to me that the boot record wants to point to the first partition (where the old boot was), and can’t be changed to point to the new boot partition where the new grub instance it located. It just seems weird. I’ll keep trying to get something operational. As always, thanks for the help so far.
We had this lately discussed, that it would need a ca. 2mb big partition if it is legacy boot. And then this partition should have the boot flag, as I remember ?! Talk: Fedora 42 Workstation installer doesn’t support Fedora re-installation on MBR disks | MBR to GPT - #8 by vekruse
There is also a Change Request that all Installations with EFI should just have a GPT instead of a MBR DosBoot record . to work with the new Anaconda installer.
That is talking about the “bios_grub” partition needed when installing grub2 on a GPT disk unit when booting in classic legacy bios mode. And, no, this does not need the boot flag.