Description of problem: Fedora 20 install media creates fat16 EFI System partitions. They should be FAT32. Version-Release number of selected component (if applicable): python-blivet-0.23.9-1.fc20.noarch anaconda-20.25.15-1.fc20.x86_64 How reproducible: Always Steps to Reproduce: 1. Do a UEFI install of Fedora Actual results: os-prober and parted report the ESP is fat16. anaconda.program.log shows mkdosfs is called without -F32 arg. Expected results: ESP should be fat32. Additional info: UEFI spec for some time has specified fat32 for system partitions, and fat12/fat16 for removeable media.
Note that some EFIs have bugs that cause them to misbehave on FAT32 ESPs that are smaller than 512MiB (note: MiB, not MB) in size. My recommendation to individuals has become to create an ESP that's 550MiB in size, since this is big enough to trigger mkdosfs to create a FAT32 filesystem by default, even if there's MiB-vs-MB confusion. A similar size might be a good choice for Anaconda, at least whenever practical.
I think we're better off letting mkdosfs handle this based on size. Is there an actual problem, eg. not booting?
(In reply to Brian C. Lane from comment #2) > I think we're better off letting mkdosfs handle this based on size. > > Is there an actual problem, eg. not booting? You could write a UEFI firmware that did this: * Works with FAT12/FAT16 ESPs on removable media, but not FAT32 ESPs * Works with FAT32 ESPs on permanent media, but not FAT12/FAT16 ESPs and it'd be spec compliant. And as we all know, that means some jackass somewhere is going to do it. I don't think we've come across a real world case *yet*, though.
Since the spec says "EFI encompasses the use of FAT32 for a system partition, and FAT12 or FAT16 for removable media" it's conceivable firmware will implement FAT12 and FAT32 but not FAT16; or FAT16 and FAT32 but not FAT12. So yes this looks like it could be a real problem. The spec also says: "For more information about the EFI file system and file image format, visit the web site from which this document was obtained." and "The rules defining the relationship between media size and FAT variants is defined in the specification for the EFI file system." Yet I'm unable to find this specification for the EFI file system anywhere.