update-grub2 could not find custom kernel

I've compiled a new kernel based on 5.4.18-xanmod10 kernel. Then I've installed it:

sudo dpkg -i linux*5.4.18-xanmod10-custom*.deb

But after installing, it have not been found by update-grub2:

root@lenovo:~# ls /boot/
config-5.3.0-29-lowlatency           memtest86+.elf
config-5.4.18-xanmod10-custom        memtest86+_multiboot.bin
config-5.5.0-3.2-liquorix-amd64      System.map-5.3.0-29-lowlatency
config-5.5.0-4.1-liquorix-amd64      System.map-5.4.18-xanmod10-custom
config-5.5.4-xanmod3                 System.map-5.5.0-3.2-liquorix-amd64
grub                                 System.map-5.5.0-4.1-liquorix-amd64
initrd.img                           System.map-5.5.4-xanmod3
initrd.img-5.3.0-29-lowlatency       vmlinuz
initrd.img-5.4.18-xanmod10-custom    vmlinuz-5.3.0-29-lowlatency
initrd.img-5.5.0-3.2-liquorix-amd64  vmlinuz-5.4.18-xanmod10-custom
initrd.img-5.5.0-4.1-liquorix-amd64  vmlinuz-5.5.0-3.2-liquorix-amd64
initrd.img-5.5.4-xanmod3             vmlinuz-5.5.0-4.1-liquorix-amd64
initrd.img.old                       vmlinuz-5.5.4-xanmod3
memtest86+.bin                       vmlinuz.old

root@lenovo:~# update-grub2
Sourcing file `/etc/default/grub'
Sourcing file `/etc/default/grub.d/init-select.cfg'
Generating grub configuration file ...
Found linux image: /boot/vmlinuz-5.3.0-29-lowlatency
Found initrd image: /boot/initrd.img-5.3.0-29-lowlatency
Found linux image: /boot/vmlinuz-5.3.0-29-lowlatency
Found initrd image: /boot/initrd.img-5.3.0-29-lowlatency
Found memtest86+ image: /boot/memtest86+.elf
Found memtest86+ image: /boot/memtest86+.bin
done

There're other kernels present, but after reboot only lowlatency kernel and memtest are present in the grub menu. Also, during update it shows the same kernel two times. Previously, before generic cernels moving to another folder, generic and lowlatency kernels have been listed during grub update.

How could I resolve this issue?

The following three commands also solve this problem, by turning off the executable bit on 09_lowlatency and turning on the bit for 10_linux, in accordance with the text in /etc/grub.d/README.lowlatency. I recommend editing /etc/default/grub to change GRUB_TIMEOUT to a positive value, prior to invoking update-grub as well.

# chmod -x /etc/grub.d/09_lowlatency
# chmod +x /etc/grub.d/10_linux
# update-grub