Accidentally I broken my system. Kernel Panic! VFS unable to mount root fs

Question

I'm on Ubuntu Impish Indri 21.10. after Upgrade Ubuntu Hirsuite Hippo 21.04 to Impish Indri 21.10, i get Kernel Panic when i boot the Ubuntu after i accidentally force do-release-upgrade

I tried to boot my old kernel but the boot is stuck on Automatic Report like below :

What did i tried

1. I tried this thread of VFS Issue, when i run this and reboot.

   sudo update-initramfs -u -k version sudo update-grub

   my both kernel and the recovery mode are stuck on Kernel Panic! VFS: Unable to mount root fs on unknown-block(0,0).

2. I tried to switch to TTY on GRUB

   Linux ... ro quiet splash 3
Linux ... ro nomodeset init=/bin/bash

   after i into the boot still Stuck on Kernel Panic.

3. I remembered i have 1000 more packages upgradable. so i plug LiveUSB and run:

   sudo fdisk -l
sudo mount /dev/sdax /mnt
sudo mount --bind /dev /mnt/dev
sudo mount --bind /dev/pts /mnt/dev/pts
sudo mount --bind /proc /mnt/proc
sudo mount --bind /sys /mnt/sys
sudo chroot /mnt
apt update && apt upgrade
update-initramfs -u -k version
update-grub

   after reboot, the boot still stuck on Kernel Panic.

Possible my main problem
i see on error output above at line:

VFS: Cannot open root device "/dev/sda7" or unknown-block(0.0)

after i checked on grub.cfg, their have different paramaters on --set-root and root=uuid=.

My partition :

• /dev/sda1 #/boot
• /dev/sda5 #/swap
• /dev/sda6 #/tmp
• /dev/sda7 #/

Well, What is the correct "root=" boot option to be?

My Kernel :

• Linux 5.4.0-90-generic
• Linux 5.4.0-84-generic

Please rescue my kernel.