Hi!
Custom images are not an option for
Oracle Always Free tier after the trial period expires.
So you can install the image from inside the vm.
If anyone interested, here's a way to do it.
1) Create instance. Under "Image and shape" choose "Rocky Linux 9.1 - Free (x86_64)". Save Private key. Create.
2) Open puttygen, "Load" the private key, "Save private key" as mikrotik.ppk
3) Open putty, "Connection->SSH->Auth->Credentials", browse for ppk on the first and private key on the second.
Return on Session and enter rocky@(your vm's public address) on "Host Name (or IP address)" box and open.
4) Execute
sudo -i
yum install unzip
umount -l /dev/sda1
curl -L
https://download.mikrotik.com/routeros/ ... .9.img.zip | funzip | dd of=/dev/sda bs=1M
sync
reboot
(you may need to force reboot it from the console)
5) Firstly check the console's firewall (Networking->Virtual cloud networks->yourvcn->Security Lists)
and the connect through the public ip and secure RouterOS from inside.