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...ISOs. It is about the size of the FAT image which serves as EFI System Partition inside the ISO. And it is about an unsurpassable limit of 16 bit numbers: If i add 1 to 65535 i get 0 as result. We have two chances with real firmware: - The Sector Count is ignored and FAT filesystem size is used insteadi as partition size. - The official values 0 or 1 are interpreted correctly and the partition spans up to the end of the medium. No problem then. FAT knows what's its own range and will not read trailing data. Of course the real firmware could bail out on Sector Count 0 or if FAT size is lar...

> Hi, > > Ady wrote: > > Is this "32MiB" a limitation related to the UEFI specs in any way? Or > > is it relevant for BIOS (non-EFI) too? > > It comes from El Torito specs which are referred to by UEFI 2.4 > specs. In EL Torito 1.0, Figures 3 and 5, "Sector Count" is a 2-byte > "Word". So it can count up to 65535. > Sector count