Prohibited sign after trying to update unsupported Mac

So I followed the steps. I think I may have made a mistake where I installed the installer to the disk first using the legacy patcher but then there was no option to select the disk during the next step. That’s when I realized I had to install it to a flash drive first and went ahead and did that. This is the only mistake I can think of because I pretty much followed the steps exactly.

After the last step when booting in the EFI. I was met with a prohibited screen. I NVRAM reset. Tried to get into recovery mode to no avail. Internet recovery worked and I reinstalled OSX to a flash drive to boot. I wasn’t given the option to use my disk and I can’t erase the disk because I have no backups of my data.

I see some tutorials showing some commands in the terminal might help

Does anyone know a solution ? Does partitioning the disk allow me to reinstall and save my data ?

submitted by /u/Calm_Comfortable_934
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