repair grub after windows updating bios on lenovo ideaPad gaming 3 AMD 7535h (15”)

Insert Debian installer DVD/CD or USB and change boot order

1. Keep press shift + restart windows -> troubleshoot -> UEFI Firmware Setting -> Restart
2. Change boot order to Debian installer media

Boot into Debian

1. Boot into Debian installer DVD/CD or USB, then press c to enter grub command. If the screen goes blank (for CD boot older then existing grub version), press ESC until you get prompt grub>
2. Get Debian partition using grub> ls and find Filesystem type ext* or your existing filesystem (see the picture below)
3. Get Debian grab from Debian partition e.q grub> ls (hd0,gpt7)/boot and find Debian grub folder  (see the picture below) 
4. Run command to start existing Debian e.q

grub> set root=(hd0,gpt7)
grub> set prefix=(hd0,gpt7)/boot/grub
grub> insmod normal
grub> normal

 

After you enter 'normal', the screen will return to GUI and your 'Debian' option will appear in boot option. Select it to run your existing debin in hard drive.

Repair grub using 

# grub-install
# update-grub

Every time you update your firmware via windows, your grub boot will lost. It's so annoying. Unfortunately, there is not much tool available to automatically check and update bios for Debian. Debian still stable using old bios, but not in windows.