[OnePlus 5 Questions & Answers] hachamacha:
The strange encryption misfire between TWRP & LOS-based OS's (questions/thoughts?)

Things we know:

TWRP and LOS-based systems with encryption either don't install correctly or boot correctly afterward. (2 different things perhaps).

Installing Magisk on non-encrypted partition gives boot loop

All LOS-based OS's must be installed on non-encrypted partitions

There is no easily found issue in the Jira issue tracker or TWRP bug tracker about this problem for the OnePlus 5.

I earlier posted this reply in the RR LOS ROM thread in response to another question about LOS-based OS's and encryption. I thought that rather than take a thread off topic, this is a better place for it. (where it can be totally ignored ;)). I shouldn't have attached this issue to a single ROM's thread since it affects a lot of LOS-based ROMs. There are other little offshoot pieces to this and some may deserve their own threads or questions at least.

TWRP: A number of people using TWRP (official or non) have problems restoring nandroid backups, which pretty much defeats much of the utility of TWRP if you can't do this. Does it have anything to do with Encryption? IT appears to, at least on the encrypted version when using the non-official version. There is a warning about it right in the thread title for non-official TWRP. I've had no problems restoring while encrypted using the official 3.1.1-1 version, but I'm beginning to feel kind of lucky in that regard.

LOS-based systems: These devices that are going to use LOS based systems require decryption of the data partition before installing whichever LOS-based ROM you're interested in. For some people, it's fine. They don't care so I don't see them as having a problem. I actually like encryption and want it, so this problem will keep me from using LOS-based ROMs until it's fixed. I've got a lot of years with Linux and Android experience, have helped with coding and customizing kernels, OSs and recoveries (mostly Philz) in the past, and would be glad to dig into the problem, at least for awhile to see if anything new can come to light but I'm not kidding myself or anyone that I can figure any of this out myself and I'm way out of practice.

Magisk: and non-encrypted partitions are also not happy together, but since I'm not too sure about the nature of that problem, I'll just call it a one-off for the moment.

Things to do: It'd be nice to figure out which area this "blob" of a problem is most likely to be in, and it'd be even nicer if one of the devs that I'll list below already knows where it is and could tell us. I can see some reason for suspecting TWRP and some reason for suspecting a combination of the OP5 FS in combination with the LOS-based ROM (or it's installer). It's not clear yet. I made a quick dirty list of some of the devs either involved with OP5 TWRP or OP5 LOS-based systems and will "mention" them in this thread in case they already know and/or are working on these things.

Another bit of this is that I signed onto Jira bug tracker (Lineage OS) to see if I could find even one sample issue that resembled this on an OP5. I couldn't but I can find some similar ones on other devices with dates only a month old. Part of this would be to try to get this either/both onto the Jira bug tracker or the TWRP bug tracker or both. Another part before that is really deciding whether this issue belongs in those places.

My question:

Clarifications of what I/others would like for the OP5 (TWRP/LOS/MAGISK) spoken of above & below:

Updates regarding latest encryption fixes in a couple of LOS-based ROMS:

I got multiple reports that CRDROID (Los-based) and Unofficial RR (LOS-based) are both now patched to work with Encryption.

SO: It looks good for LOS-based ROMs now. 2 out of ~9 or 10 of them are working so they'll all be working with encryption (and without) soon enough. I'll kill off that part of this thread and concentrate more on getting the full-featured TWRP we can all use:

TWRP should be able to:

There's a few devs I'm aware of that work on it for OP5 but I'm not going to bug them just yet. I want to be more sure I know what each version of TWRP (off and non-off) can do and can't.

More updates about ROMs and TWRP's:

Looks possible that TWRP (Unofficial) just took a leap forward and is doing a bunch of things right:

Thanks for carrying on the battle. So far it seems good to me, so nice work! -- I just installed, plugged in and mounted OTG device and did a full (all partitions) encrypted backup to the usb-stick, then restored it. I saw no red characters, and I may have forgot to save the log (doH!) but will look in the backup folder in a bit.

Currently I'm running noLimits with Elemental 1.06. No problems. Oh yeah, themes working fine as well. Unless something odd crops up, this could be a real recovery.

Good work to you guys for persevering.

Other things tested: Sideload mode OK; Adb shell OK. Installed xXx ROM latest version with another kernel: OK.

-- Probably this will be the last entry since a fully functional TWRP was a big thing on the wish list and it appears to be here. The thread is the "Unofficial TWRP" thread currently, but maybe it'll be renamed.