Use this better tutorial: https://gist.github.com/karolba/a3f1c5f8d50c67f5a19e6c8f38e53e12

---

1. Reboot into the rescue image
2. Then execute these commands:

cd /dev/shm
mkdir alpine
cd alpine
wget https://dl-cdn.alpinelinux.org/alpine/v3.16/releases/x86_64/alpine-minirootfs-3.16.0-x86_64.tar.gz
tar xzvf alpine*
mount -t proc /proc proc/
mount -t sysfs /sys sys/
mount --rbind /dev dev/
cp /etc/resolv.conf etc/resolv.conf
chroot . ash -l
apk add alpine-conf nano

3. nano /sbin/setup-disk
4. Set return 1 to return 0 for is_efi
5. nano /sbin/setup-alpine
6. add -s 0 -k virt after setup-disk
7. setup-alpine
8. Then:

exit
mount /dev/vda2 /mnt
chroot /mnt /bin/ash
cd /boot/grub
nano grub.cfg

9. Add console=ttyS0 for line linux /boot/vmlinuz-virt
10. Then execute this commands for having a proper boot:

rc-update add modules boot 
rc-update add hostname boot
rc-update add dmesg sysinit
rc-update add devfs sysinit
rc-update add acpid boot
rc-update add bootmisc boot
rc-update add hwclock boot
rc-update add sysctl boot
rc-update add syslog boot
rc-update add mount-ro shutdown
rc-update add mdev sysinit
rc-update add killprocs shutdown
rc-update add hwdrivers sysinit
rc-update add crond
rc-update add local

10. Add your key in /mnt/root/.ssh/authorized_keys
11. umount /mnt
12. Reboot

Extra for correct serial:

1. Add this in /etc/default/grub:

GRUB_TERMINAL="serial console"
GRUB_SERIAL_COMMAND="serial --unit=0 --word=8 --parity=no --speed 38400 --stop=1"

2. Add console=ttyS0,38400n8d to GRUB_CMDLINE_LINUX_DEFAULT
3. grub-mkconfig -o /boot/grub/grub.cfg
4. Add ttyS0::respawn:/sbin/getty -L ttyS0 38400 vt100 to /etc/inittab

Source: https://riedstra.dev/2019/09/alpine-gcp