First LOS installation and missing steps from the Wiki

[fairywax]

Hello everyone, first post here.
[pre-submitting edit: I'm new so no external links, sorry if they are garbage]

tl;dr
Installed LOS 16 on crackling, the LOS Wiki should be updated, here the issues I had to solve:

1. When preparing the phone, TWRP complains about /system having squashfs filesystem; solved by formatting the /system with ext4 filesystem;
2. Sideloading LOS 16 on stock Android 7.1.2 gives an unbootable OS; solved by downgrading first to stock CynogenOS (Android 6);
3. Encrypting the phone does not work; solved by resizing /data via TWRP.

Long story
I installed LineageOS on a Wileyfox Swift running the stock Android 7.1.2, I followed the wiki wiki_dot_lineageos_dot_org/devices/crackling/install but I had to solve a couple of issues that were not documented there. Before proposing any changes to the wiki, I would like first to understand if the issues are well known and what causes them.

Issue 1: TWRP complains about /system partition being formatted with the squashfs filesystem
Following the wiki, at wiki_dot_lineageos_dot_org/devices/crackling/install#installing-lineageos-from-recovery, step 5 says:

...tap Advanced Wipe, then select the Cache and System partitions and then Swipe to Wipe.

here TWRP complains about the partition /system being formatted as squashfs. The problem does not permit a successful sideloading of LineageOS, and the solution seems to be formatting the partition with the filesystem ext4.

Questions:

• Is it common to have the partition /system with squashfs filesystem? Or is it only the Swift having it like this?
• TWRP complains about it just because it does not support squashfs? Or are there other reasons?
• Do other recoveries support the squashfs filesystem?

Issue 2: LineageOS 16 is unbootable if sideloaded on stock Android 7.1.2
If sideloading LOS 16 on stock Android 7.1.2, the phone only reboots at fastboot. I found some possible solutions at www_dot_reddit_dot_com/r/LineageOS/comments/9pcgrh/cant_start_lineage_stuck_at_fastboot/: downgrading first at CyanogenOS, or installing crDroid, or using the FoxyKernel. As per the discussion, the problem looks like being the 'new bootloader'. I tried downgrading first to CyanogenOS, which should have installed the 'old bootloader', and it solved the problem.

Questions:

• When was the 'new bootlaoder' introduced (Wileyfox Android 7?) and what is wrong with it?
• Does the problem lies at kernel level? If so, only crDroid and FoxyKernel have the required changes?

Issue 3: Encrypting the phone fails because of something wrong with the /data partition
After a fresh installation and first configuration of LOS, encrypting the phone just fails: the phone shows a black screen, it flashes the main screen after every few seconds, then it reboots after an hour or so without being encrypted at all. The solution is suggested at gitlab_dot_com/LineageOS/issues/android/-/issues/700: to perform a filesystem resize of the /data partition via TWRP.

Questions:

• What is wrong with the /data partition after following the LOS installation procedure?
• What does the TWRP filesystem resizing actually do? I don't think it increased/decreased the /data partition at all!

And bonus question: Did someone else experienced the same issues? Are they known?

 

[Telcoced]

Had issue 2 once, found a workaround thanks to @beroid, https://forum.xda-developers.com/showpost.php?p=66158015&postcount=2 can't answer precisely your question unfortunately.

 

[zomgzerg]

The official OS messed with the file systems when they went from the original CyanogenOS based Android 6 to whatever they used for 7 with the Russian launcher