Using small USB keys for bootloaders

[Nodarkthings]

I want to share this little trick, useful if you have old USB keys of little capacity (say 1GB): usually they will be formatted as MBR with a FAT32 partition. Well, I've discovered that the EFI partition's size doesn't matter for our bootloaders as long as it's called "EFI" (I'm currently using OpenCore, but it works the same with Clover, even Legacy).
So I'm formatting my key with GUID partition table and a single FAT32 partition called EFI where I put the OpenCore EFI folder.

This is not a revolution, but I find it convenient for testing purposes (with OpenCore's monthly upgrade, for example), as you don't need to monopolize your big USB key for just booting (and I've read more than once people who think you need the big MacOS installer key to boot...)
So, don't yell at me if it's obvious to you, I think it might be useful for beginners too.

 

[miliuco]

@Nodarkthings
Useful! It’s a good role for our old USB sticks. Thanks.

 

[1Revenger1]

Doesn't even need to be named EFI - just needs to be a FAT32 partition. If your using the method of putting macOS recovery in the same partition as OC, I don't think it even needs to be GUID? Using smaller USBs just for testing bootloaders is definitely really nice though.

 

[atl285]

I'm using this method about 6 months or longer and very happy with it. I put the USB stick into an internal USB header (via adapter). And the internal USB ports I use, are not mapped for OSX. This solution has some advantages for me:

• I don't lose an USB port for macOS
• the EFI can't be destroyed by mistake (I use macOS only on the system)
• my SSDs / HDDs are EFI-less and can used in other Hackintoshs or real Macs

I've at least 2 sticks, one labeled with "PROD" and one with "DEV". The "PROD" stick is for daily and productive usage. The "DEV" stick is used to test new or modified EFIs, for example on OpenCore updates.