[P8lite Q&A, Help & Troubleshooting] Jujub:
Some advice from a beginner

Hi!

So, I installed Lineage OS 17.1 on my sister's phone just two days ago, maybe I can give you some advice being myself a beginner. So, first of all, I guess you have enabled OEM unlock (otherwise you could not flash TWRP I guess? I don't think this is the point anyway) If not so, go to Developer Options --> Enable OEM unlock and you will see both the bootloader and FRP unlocked.

The try to follow the DarkJoker360's Lineage OS 17.1 install guide step by step (don't forget to flash the los_patches_prague.zip!). The right version of TWRP is important too for compatibility issues, so install the version he provided.

Anyway, as [MENTION=7294734]DunoCZ[/MENTION] pointed out, for entering TWRP recovery you have to press Volume UP button + Power button and keep them pressed until you get to the TWRP. Otherwise, what the device does is either booting up or go to the screen like "Press Volume UP for at least 3 seconds to go to erecovery" and if you do that, it will go into Huawei's own recovery.

Another thing is... Did you do a full wipe (system, data, cache, dalvik/art cache) in TWRP before trying to flash the new ROM? (don't just do the factory reset in Huawei's recovery, I read somewhere it doesn't wipe everything like the advanced one in the custom recovery)

Because as you wrote here, the stock OS booted up before you installed stock from again via Huawei erecovery. So my wild guess is that the wipe you did before flashing Lineage OS wasn't a full wipe?

---------- Post added at 10:30 AM ---------- Previous post was at 10:06 AM ----------

By the way, after installing Lineage OS 17.1 I found out there were indeed some very important problems in the ROM as noticed by other testers too...

The reason why I changed the ROM on the device was mainly because of two reasons:

1) Short battery life :rolleyes:

2) Not enough memory :(

And unfortunately, on Lineage OS 17.1:

1) Battery life not good enough. Unless you fix it by patching a new kernel, be always wary of apps running on your device etc., the battery ran short even after replacing the internal battery. Alas. Besides, I wanted something stable for my sis who threatened me to buy an iPhone if I couldn't fix her phone lol

2) Very big problem with memory: I couldn't find a way to write to the SD card as other users pointed out. It is read by the device, but apparently it is read only and even with root permissions I couldn't find a way to obtain write permission for the apps. Perhaps some options in fstab mount file should be changed, but honestly, I tried with my below-average knowledge of Linux and gave up :crying:

But then... I tried Lineage OS 15.1 and this one worked much, much better. Battery life is super good and has the adoptable storage option for the SD card! This way, instead of those 9 gigs of memory now the phone has more than 70! And honestly, this ROM solved both the most important problems of this phone :D

(PS: sorry for the long posts lol)

(PPS: if you decide to switch to 15.1, remember to decrypt the memory following this post otherwise you won't be able to install more that a bunch of apps on the phone. Besides, remember to flash Dil3mm4 's TWRP recovery)