A EFI partition is mostly read-only, so I don't think that's a particularly large problem? > I would rather use Ext4 everywhere for everything. Is the problem

A EFI partition is mostly read-only, so I don't think that's a particularly large problem? > I would rather use Ext4 everywhere for everything. Is the problem preventing wide adoption of Ext4 GPL? The BSDs don't support ext{2,3,4} particularly well, and Linux doesn't support FFS/UFS particularly well. I mean, there's support for these things, but it's far from complete or perfect and it's taken a long time. It's just a fair amount of effort to implement filesystems well, and there's very little tolerance for errors. Ext4 isn't spectacularly complicated, but it's not exactly a simple FS either. I think that has more to do with lack of support than anything else: lots of effort for not all that much practical benefit.