Leap 15.5 will not boot

I installed 15.5 on partition 5 of drive sda without any problems, but it would not boot. So I invoked grub2-mkconfig to be sure, and it shows 15.5 as being identified. But it does not show in the grub menu at boot time.

Device         Start        End    Sectors   Size Type
/dev/sda1     616448   17000447   16384000   7.8G Linux swap
/dev/sda2   17000448  100968447   83968000    40G Linux filesystem
/dev/sda3         34     616447     616414   301M EFI System
/dev/sda4  100968448  182888447   81920000  39.1G Linux filesystem
/dev/sda5  182888448  259860479   76972032  36.7G Linux filesystem
/dev/sda6  260065280 1953525134 1693459855 807.5G Linux filesystem
/dev/sda7  259860480  259876863      16384     8M BIOS boot


:~> sudo grub2-mkconfig >>xxx
[sudo] password for root: 
Generating grub configuration file ...
Found theme: /boot/grub2/themes/openSUSE/theme.txt
Found linux image: /boot/vmlinuz-6.5.4-1-default
Found initrd image: /boot/initrd-6.5.4-1-default
Found linux image: /boot/vmlinuz-6.5.3-1-default
Found initrd image: /boot/initrd-6.5.3-1-default
Found linux image: /boot/vmlinuz-6.5.2-1-default
Found initrd image: /boot/initrd-6.5.2-1-default
Found linux image: /boot/vmlinuz-6.4.12-1-default
Found initrd image: /boot/initrd-6.4.12-1-default
Found linux image: /boot/vmlinuz-6.4.9-1-default
Found initrd image: /boot/initrd-6.4.9-1-default
Found linux image: /boot/vmlinuz-6.4.8-1-default
Found initrd image: /boot/initrd-6.4.8-1-default
Found linux image: /boot/vmlinuz-6.4.6-1-default
Found initrd image: /boot/initrd-6.4.6-1-default
Found linux image: /boot/vmlinuz-5.19.1-1-default
Found initrd image: /boot/initrd-5.19.1-1-default
Warning: os-prober will be executed to detect other bootable partitions.
Its output will be used to detect bootable binaries on them and create new boot entries.
Found Debian GNU/Linux 12 (bookworm) on /dev/sda4
Found openSUSE Leap 15.5 on /dev/sda5
Adding boot menu entry for UEFI Firmware Settings ...
done

You invoked it where? You apparently have three instances of Linux on sda and you should start with explaining what is installed where, which instance controls the booting and where you run all those commands.

You show some output of unknown command which makes it less useful than it could be.

Having both legacy BIOS and EFI boot on the same disk usually means that something is not right. I do not say it necessarily explains your particular problem, but if you have non-standard configuration you better explain it, so that others can also understand why you have it.

So show resulting xxx. Compare xxx with grub.cfg. If they are different, copy xxx as grub.cfg.

I ran grub2-mkconfig from the booted Tumbleweed (sda2). It and the Debian on sda4 both boot. The drive data is from fdisk /dev/sda. It showed more than gdisk. I think the BIOS boot sector might have come with the Debian install, but as both Tumbleweed and Debian boot I never questioned its need.

I copied xxx to grub.cfg as they were different, ran grub2-mkconfig and I can now boot 15.5. Thanks for the speedy solution.