PRS-T2 Downgrading Firmware?

I've recently found my old E-Reader (Firmware Version 1.1.00.17210), so I thought, let's jailbreak it, why not?

But I'm stuck on the Firmware or rather booting into recovery mode and connection via Serial to my PC.

So far I've tried:

• Holding Home and Menu Button during booting (just boots like normal)

• Enabling Test Mode (Made a File "rVPzp8O1j0m01oOq.crsZVu8crtmXGrc2", pressed right-back-left-back) and tapping "Reboot (Recovery)" -> It takes a bit longer to boot, when Opening Book is at 100% the screen flashes and restarts normally

• Put OS-Firmware from Rupor Rescue on my MicroSD Card and "Reboot(Recovery)"->Literally the same thing as without that folder

• ebook_msc.exe name "PRS-T2" um recovery

• rupor-minimal,-jailbreak,-enabled-adb (said unsupported Firmware Version), restore-set-1.00.xxxxx-eu (I live in the eu), PRS-T2_UPDATER(Doesnt do anything, and removing the code that checks for current FWV just reboots, then says failed), mount_all_plus_serial

• And a few more things

The main Guide I follow should probably work, even though its for the PRS-T1, so (I hope) my main and only problem is this recovery mode issue or rather downgrading FW of my E-Reader

Also, yes, my SD is Fat32 formatted and it's 16GB, though I've made only one partion of 6GB and left the rest unused. I've also formatted the Ereader itself afew times just to be sure but nothing changed

Thanks in advance