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Using small USB keys for bootloaders

Joined
Jul 11, 2012
Messages
450
Motherboard
Gigabyte GA Z68XP-UD3
CPU
i7 3770
Graphics
GT 210
Mac
  1. iMac
  2. Mac mini
Mobile Phone
  1. Android
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. ;)
 
Joined
Feb 23, 2020
Messages
134
Motherboard
Dell Precision M4700
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i7-3740QM
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M4000
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.
 
Joined
Dec 23, 2019
Messages
39
Motherboard
Gigabyte Z390 M Gaming
CPU
i9-9900K
Graphics
RX 580
Classic Mac
  1. Power Mac
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.
 
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