Steps done:
1. apt-get purge system-service && apt-get install install system-services # my rcS-late differed from stock and I decided to put it back to stock, simple --reinstall didn't overwrite rcS-late
2. adjusted ereswap config and done ~/.config/ereswap/adjust-rcS-late.sh
3. disabled swapset (in case of a potential conflict) - simply commented out the swapset startup line in the upstart script
4. rebooted - everything was fine
5. the next day (today) while using the microb browser, the device crashed (so the bootup went ok)
6. After switching on the device, a nokia logo appears for a couple of seconds. Then it dies. If connected to a charger, it regularly vibrates and shows a dim nokia logo.
I do can access bootmenu but due to hardware damage I can do only one keypress. So maybe rescueOS or rescue initrd as a recovery option?

I'm wondering: what can be the cause?
And is it possible to get it back working without a reflash?

I can only assume some modified upstart script.
The two programs could have conflicted somewhere as they work in a similar way.
Remember if an upstart file fails it is run with '-e' so the whole file fails.

I am not a fan of the way ereswap modifies upstart scripts and TBH I don't think compcache is helpful on our devices. This is why I made flopswap. (plug )

Yeah, but if it was a faulty upstart script, it wouldn't have booted the previous time! And since the last boot no changes in upstart scripts have been made. Another question which came to me - why did it stop booting after the crash and why did the crash occur?

/edit: btw. ereswap wiki says nothing about compcache

/edit2: it's why I disabled swapset

Me too But I'm even less a fan of enabling swap on eMMC and disabling it a split second later (or having to keep swap on eMMC at all, if I want to get rid of it). AFAIK modification of rcS-late was only possible way to enable swap where we want it from the very beginning - but, things might have changed since I've checked it last time, so feel free to correct me.

Rightly so, as it doesn't have anything to do with compcache

As for you problem - I think that your edits might have been a coincidence. I would rather blame that crash - hoever, failing to boot in so early stage doesn't look like filesystem damage...

You're using u-boot, right? Does it show up properly? If yes, then rescueos is a way to go. Otherwise, you're out of option and must try reflashing, and pray that it isn't hardware damage. Don't want to scare you or anything, but it looks awfully like one.

/Estel

As I say I designed flopswap differently because I had different ideals. We have covered this before...

It's hardly enabled and a none issue really IMO. At least if something screws up you don't end up in a boot loop.
Without integrating a swap management system into CSSU there is no better way AFAIK.

Not everyone wants to glue a magnet to the back of there device.
It's nice to be able to unmount the card for removal while the device is on.

Swapset has compcache not ereswap

Some service or module must be failing on boot up. I would normally be looking at what I played with last.
http://wiki.maemo.org/Maemo_5_boot_process

RescueOS, bm or a rootfs flash should do the trick if it's not hardware related.

Also note that while bootlooping the battery will not charge. You will have to charge the battery in another device or external charger.

Well, I finally ended up reflashing and it did the trick

Well at least you know it wasn't hardware related now.

Yep
But I wouldn't have wondered if it hadn't been, in fact, hw damage It's already hw damaged to some extent

regarding magnets + swap. worst I've ever had was watching a vid when early for work. opened kickstand and magnet fell off onto a black sparkly floor, phone rebooted and i panicked. somehow after searching round and giving up, i did manage to spot it. just meant i had to put magent and stand together, hold stand in and leave it in case until i could get home to put some contact adhesive on it.

after reading you problem, makes me think i really should set up uboot and co.