Different EFI partition sizes

[HRmac]

What’s the deal with different EFI partition sizes on Mac? When running ”diskutil list” command most of macs show size 209.7 MB on EFI (disk0s1).

My Macbook Pro (3rd party SSD) and Macbook (3rd party SSD) show 209.7 MB but for some reason my iMac (18.2) (Apple SSD) shows 314.6 MB. All of them are running High Sierra (no Boot Camp installed). I’ve bought iMac used but it has been factory reseted.

What’s the reason for different EFI partition sizes?
Is there something wrong with EFI or OS installation.

 

[HRmac]

314.6 MB seems to come from 209.7 MB (Mac) + 104.9 MB (Windows).

If this is the case Apple’s factory reset is completely joke and previous owner did have boot camp installed.

I mounted EFI but didn’t see any windows folder. I didn’t touch anything.

EFI volume contained BOOTLOG file and EFI folder.
EFI folder contained APPLE folder
APPLE folder contained EXTENSIONS, FIRMWARE and UPDATERS folder.

 

[Brian33]

My Mojave Late 2015 iMac has bootcamp installed, but it's EFI partition is also 209.7 MB. I don't know why your iMac's is bigger.

I'm not sure what you mean that the iMac has been "factory reset." I'm not aware of any Apple "factory reset" that would have any effect on the storage (hard drive or ssd). There's a NVRAM reset and an SMC reset, but again, neither of those would affect a hard drive. The only way to "reset" a hard drive is to boot from some other drive and repartition/format the first one (I believe Disk Utility's "Erase" function does that).

 

[HRmac]

"Factory reset": https://support.apple.com/en-us/HT201065. It might be that apfs volume was erased not the whole disk.