509      iPhone_iPad_Mac_apple

Firmware Error while trying to upgrade to macOS...

Hello,

I have 13" MacBook Pro Retina (Early 2015) and no matter what I try High Sierra wont install.

I did all the repair disk with disk utility but nothing changed. I have tried to install it from an external USB Drive with no luck. Also I installed the original 128GB PCIe SSD but again same firmware error. I now have a 500GB Original Apple Samsung PCIe SSD.

I was thinking that this might be a regional error ? This MacBook Pro is a US model and I am located in the EU. My Apple Store account is EU also.

Anybody any ideas ?

Thank you in advance.

最后更新：2017-10-04 15:08:41

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