The format is actually a subset of FAT, not HFS+. The GPT entry's type should be C12A7328-F81F-11D2-BA4B-00A0C93EC93B, and if you have a hybrid MBR, the type there should be EE. It should start at sector 40, and it should be 409600 sectors (exactly 200MiB) long. You can recreate the EFI System Partition (ESP) using the command-line gpt tool. My question is (without formatting the disk) how do I create an EFI partition?
This didn't seem to create the correct type of partition, it created an Apple_HFS instead of EFI. #: TYPE NAME SIZE IDENTIFIERĢ: Apple_HFS Macintosh HD 799.0 GB disk0s2ģ: Apple_Boot Recovery HD 650.0 MB disk0s3Ĥ: Microsoft Basic Data BOOTCAMP 200.3 GB disk0s4Īs you can see I've had a go at fixing the EFI partition with the following command: Mountain Lion won't install without a valid EFI partition. However now I want to install Mountain Lion and there's a whole heap of trouble. I did notice that the EFI firmware updates failed to install, but paid this no mind. I didn't really realise the significance of this as the machine continued to work fine, booting both into Windows and OSX. During the install of Windows 7 I wasn't paying complete attention and deleted and formatted the EFI partition.
