I'll try those. Bear in mind that in SFOS 4.0.1 all services have moved from /lib/systemd/ to /usr/lib/systemd ! (I've realised this on my Note4 port when, after the boot, none of my services started.

To fix your SDK I recommend you to delete these folders (with all their contents) and then set them up from scratch again:

• sdks
• targets
• toolings

Then, for building 4.0.1, update all three submodules:

• rpm/dhd
• hybris/droid-configs/droid-configs-device
• hybris/droid-hal-version-$DEVICE

This time you'll need to update the mer-kernel-check as well because there are a few extra kernel requirements for this new release.

Oh, yes and one more thing before you start building:
delete hybris/mw/libhybris folder and do a clean up on the hybris/mw/libgbinder (in the sdk: cd hybris/mw/libgbinder; git clean -x -f -d).
Then you won't get errors like I did.

Oh, and the last one. When you create tooling and target, use the direct link rather than the *latest* because the latest is not pointing to the latest yet! (you'll need the URL that starts with Sailfish_OS-4.0.1.45*)

Good luck!