mmh, Откуда взял, что у Вас MBR - может приснилось, но вот ваше высокомерие я таки попрошу попридержать
Although the EFI specification is mute on the subject of the ESP's size, most OSes make it fairly small—Macs ship with 200MiB ESPs, and the Windows 7 installer creates one of just 100MiB. (That value has been raised to a bit over 200MiB on newer versions of Windows.) Some users, however, have found that some EFIs have bugs that cause problems with FAT32 ESPs that are under 512MiB (537MB) in size. One very common problem is files that can't be read by the EFI. The Linux mkdosfs command defaults to using FAT16 for partitions of up to 520MiB (546MB). Therefore, adding a margin of safety to protect against MiB/MB confusion and rounding errors, I recommend creating an ESP that's at least 550MiB in size. If you must use a smaller ESP and if you encounter mysterious problems, try converting it to FAT16; most ESPs will work fine with this, and it may eliminate your problems. On the other hand, this may cause the Windows installer to fail should you need to install this OS.
Хз откуда инфа. За ограничение размера файла в fat32 знаю, за ограничение размера диска - первый раз слышу.
Но вот об этом вкурсе MSDN - окошками вы не форматнете более 32ГиБ в FAT32, только сторонним ПО\другой ОС. Даже скажу больше, 2000 окошки не распознавали более 128ГиБ на диске без специального патча.