Huawei P8 Lite 2015 (ALE-LX1) Custom Recovery broken

[fzp0]

Hello, I successfully unlocked my 2015 P8 Lite bootloader. The issue is when I want to install a custom recovery image (TWRP), the fastboot software gives me an error "remote: image verification failed".
I looked around on various forums and the only plausible cause is that after unlocking the bootloader with PotatoNV, it changed the factory unlock number and now the phone doesnt want to accept the new recovery image. Unfortunately PotatoNV changes the unlock code when unlocking the bootloader and in addition doesnt log the output to a file, so I dont even have the original unlock code to restore it with an older version of PotatoNV (the newest one doesnt support custom codes, just sets it to a random string from what i know). At least when i exit out of fastboot the phone boots into default EMUI, so it isnt bricked.
So I have 2 questions: Is there any way to restore the factory unlock code or bypass the image verification check? If not, is there a way to load a custom OS without a custom recovery?
If there is really no hope for me to load recovery/OS on this phone, treat this discussion as a request to remove changing the default unlock key by default and implement logging into the software.
Thanks for reading.