To follow up on this (in case you see ever see this comment) - I don't think that the linked article suggests that rooting the phone -permanently- damages anyth

To follow up on this (in case you see ever see this comment) - I don't think that the linked article suggests that rooting the phone -permanently- damages anything. To me, that reads more like "the phone's bootloader checks to see whether it's booting a signed kernel. If not, it tells the battery controller to limit charging capacity until the next boot." In this particular case, it was probably a safety thing on that particular phone. I bet that Samsung pushed it in a firmware update because of their "batteries catch fire" issue, which was fixed with some patches to the kernel driver. Chances are this was intended to make sure that somebody running an unsigned/homebrew kernel (which might or might not have the patched charge-controller drivers) wouldn't be able to make their battery catch fire.