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