I deleted all of the mounts and directories on the Unraid server and inside the MariaDB container too. Then recreated it, and seems to be working as above. Not sure which permission was causing the issue, might have been the first output file and afterwards the script would need to update an existing file.
I think it was the use of USB2.0 flash drives to deploy this too, in combination with restricted ability to boot using only the USB2.0 ports.
I had to use a Ubuntu Live to boot from, to give me a Linux environment that I could run these commands on. This needed a USB2.0 device.
I had previously then been using a USB3.x (tried 3.1 and 3.2, given what I had to hand) to install UNRAID onto. I thought I had booted from one of these USB3.x devices - but I expect I was getting confused with the combinations I had been trying.
So re-create the partitions on the USB2.0 device from the `fdisk` commands in the first link.
Once the `mkfs.fat` command is issued and the /dev/sdX1 has been labelled as "UNRAID", I switch to the second link, to install Grub. I actually swapped between both guides here actually, and installed all 3 `grub-install` configs (just in case!).
Now I have my FIRST booted unRAID running, I now have to learn how to use it!
Thanks so much for people's inputs and trying to inform and guide me. It was all appreciated!
