Thanks for brainstorming!

The issue is that I am unable to create partitions on a disk what is not present. Unfortunately mmcblk0 is not present in /dev. The OS is not seeing the drive.

My idea was to modify the rescue scripts (luckily it is working with variables). It was successfully created the partitions on a HDD (/dev/sda). The problem is that on a restary it re-reads the ROM and wants to boot from mmcblk0 not sda.

My idea is to extract the rescue image file. modify the scripts, and re program ROM with the modified one, to work from sda instead.

Basically the mmcblk0 drive seems defective.