Alpine linux how to load system into RAM

I need advice if possible to load entire system into RAM. Let's imagine following situation: Booting LIVE OS from DVD and login as root lsblk shows

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
loop0    7:0    0  2.9G  1 loop 
sda      8:0    0 19.1G  0 disk 
|-sda1   8:1    0    1G  0 part 
`-sda2   8:2    0 18.1G  0 part 
sr0     11:0    1 1024M  0 rom

I cannot do netboot with ipxe because I will need to have VPN. The only option here is to use DD and overwrite existing /dev/sda with my custom alpine.img I will use qemu and apline linux virt image. Here are the steps I have done so far: - Booted Alpine linux from iso and created /dev/sda - sda will bave only boot partition as mounting point as following:

NAME   MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
sda      8:0    0    1G  0 disk 
├─sda1   8:1    0  300M  0 part /boot

- in /boot directory I have copied following:

/boot/
├── alpine-rootfs.tar.gz
├── System.map-virt
├── boot -> .
├── config-virt
├── extlinux.conf
├── initramfs-virt
├── ldlinux.c32
├── ldlinux.sys
├── libcom32.c32
├── libutil.c32
├── lost+found
├── mboot.c32
├── menu.c32
├── vesamenu.c32
└── vmlinuz-virt

extlinux.conf contains

# Generated by update-extlinux 6.04_pre1-r15
DEFAULT menu.c32
PROMPT 0
MENU TITLE Alpine/Linux Boot Menu
MENU HIDDEN
MENU AUTOBOOT Alpine will be booted automatically in # seconds.
TIMEOUT 10
LABEL virt
  MENU LABEL Linux virt
  LINUX vmlinuz-virt
  INITRD initramfs-virt
  APPEND root=/dev/ram0 modules=sd-mod,usb-storage,ext4 quiet rootfstype=ext4

In the initramfs-virt I have added following code:

# Create a RAM disk with a filesystem (adjust the size as needed)
mkdir -p /sysroot
mount -t tmpfs -o size=512M tmpfs /sysroot
# Extract the contents of your root filesystem (e.g., Alpine Linux) to the RAM disk
tar -xzvf /path/to/your/alpine-rootfs.tar.gz -C /sysroot
# Pivot to the RAM disk as the new root filesystem
exec switch_root /sysroot /sbin/init

Unfortunately boot process fails, Can someone advice what am I doing wrong here The whole point here is to have following solution: - Once rescue DVD is booted use dd to overwrite existing /dev/sda with my custom alpine.img - next boot from custom alpine.img and load system into RAM - once you login to shell create ssh tunnelling and deploy final operating system