SD cards being "plain block devices" don't preclude the internal controller of relying on presence of the specific layout. the requirement of having it specifically formatted is part of the spec (SD Specifications Part 2 File System Specification), it's not available openly, but it is there, and thus noone can certainly claim, that any vendor don't use this reliance when creating their firmware. "users can format with anything blablabla" becomes a try-and-see*. of course, not every hang you encounter on these "tinkering" platforms, running, let's be honest, suboptimal and rough software should be attributed to SD card malfunction due to the incompliant layout, but it could be one of candidates. no, you can't use FAT for linux boot/install target volume, since it doesn't support that, you just need to keep in mind, that using SD cards this way is unsafe and if you want stable system, you'd better to migrate to internal storage ASAP. SD cards are removable storages, optimized for that scenario.
for me, the value of things like Pinephone firstly is being open platforms. that is, platforms letting you do with them much more, compared to locked down counterparts. it's not aligned with being fanatically 100% opensourced, open documentation and its quality is much more important. for example, that modem thing, it's not opensourced at all, so what? but if interaction with it, programming model for the host is documented, it's the thing, what is really needed. if some guy made a nice system, letting users do multibooting, but decided, that parts of that system cannot be opensourced, is this a stop factor for the users to not use that system? why? after all, they need multiboot capability from that system, not its opensourceness. the latter could really be of interest for those willing to join the effort in making that system. they should contact the creator and clarify about it. turning opensources in a self goal looks like an irrational thing, something religious-like. that's not cool.
* - neither Windows nor Android won't format an SD card with anything other than FAT and I think the same applies to iOS.
for me, the value of things like Pinephone firstly is being open platforms. that is, platforms letting you do with them much more, compared to locked down counterparts. it's not aligned with being fanatically 100% opensourced, open documentation and its quality is much more important. for example, that modem thing, it's not opensourced at all, so what? but if interaction with it, programming model for the host is documented, it's the thing, what is really needed. if some guy made a nice system, letting users do multibooting, but decided, that parts of that system cannot be opensourced, is this a stop factor for the users to not use that system? why? after all, they need multiboot capability from that system, not its opensourceness. the latter could really be of interest for those willing to join the effort in making that system. they should contact the creator and clarify about it. turning opensources in a self goal looks like an irrational thing, something religious-like. that's not cool.
* - neither Windows nor Android won't format an SD card with anything other than FAT and I think the same applies to iOS.
ANT - my hobby OS for x86 and ARM.