[Wileyfox Swift] 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:

When preparing the phone, TWRP complains about /system having squashfs filesystem; solved by formatting the /system with ext4 filesystem;

Sideloading LOS 16 on stock Android 7.1.2 gives an unbootable OS; solved by downgrading first to stock CynogenOS (Android 6);

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:

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?