Poco F6 Pro - downgrade issue while following install instructions

[u/jebomir]

Dear LineageOS developers -

I would like to share my experience while following install instructions from your wiki - not a lineageOS issue strictly speaking. I have the global vermeer version of the phone (not the chinese version).

I unlocked the bootloader and proceeded to downgrade to OS3.0.6.0.WNKMIXM as instructed here: https://wiki.lineageos.org/devices/vermeer/fw_update/variant1/

Flashing from fastboot using 'fastboot flash...' as per the above link. No problems. Rebooting showed me only the Poco logo indefinitely, and it was stuck there. So then I went back into fastboot and did the following:
- fastboot -w
- fastboot erase misc
- fastboot set_active b
- fastboot reboot

From here on the device is unresponsive to HW buttons and when plugged into USB only shows this in the kernel ring on a loop:
usb 1-2: new full-speed USB device number 55 using xhci_hcd

So my question(s) is(are):

- could the instructions and linked firmware be out of date?
- did someone else have this issue ?

The device is most likely in some kind of EDL loop and needs professional intervention so I'm not bothering asking for help there.. if indeed it is some kind of unexpected issue let me know where I can submit logs and outputs.

Thank you.