Is there a way to reduce the time spent in EFI?

It seems more than 15 seconds that the Mac (Macbook air 2011) stays with the screen grey before beginning to boot (or resume from hibernate) to Windows.

Booting into MacOS is faster and getting to the grey apple symbol is very fast.

This video shows it: https://www.youtube.com/watch?v=HITe9-VOrDI

I need to add that I currently run Windows 10, but did boot camp assistant with Win7 because no native support of boot camp for my hardware and no Win8 product key.

Within Win10 it shows me: BIOS Mode Legacy and SMBIOS Version 2.4

(please give me a hint if you think this subject is better placed on a Windows part of Stackexchange.)

  • I think I am stuck to slow boot with mid 2011 macbook air if there is no update oft EFI to UEFI, which probably will not happen. – Falco Alexander Sep 15 '15 at 12:56
  • I think this question is quite on-topic for apple.stackexchange.com. – D A Vincent Sep 30 '15 at 1:38
  • 1
    I just edited my answer below with more info – Falco Alexander Sep 30 '15 at 6:39
  • Same problem here w mba 2011 win 10 dark screen glitch was annoying enough I decided to go back to Windows 8 except now it keeps asking me to install windows 10 hopefully Apple produce updated drivers and a Boot Camp for these old mbA – Prashant V. Phatak Jan 19 '16 at 20:05
  • as in my answer: you can install Win10 fine, but you need to boot by BIOS emulation, NOT (U)EFI – Falco Alexander Jan 22 '16 at 11:03

I have a 20-inch mid 2007 iMac running OS X 10.10.5 and Windows 10 Pro 64 bit. Both were cleanly installed. This means before installing there was no previous version of ether operating system and the partitions were reformatted. Now, I would expect my boot times to be longer than yours. The strange thing is both operating systems take the same amount of time to boot. The time is about 64 seconds. Both operating systems are set to auto boot directly into my account.

If your Windows 10 is activated, then you can preform a clean install of Windows 10 using the latest Boot Camp drivers available for your Mac. Once connected to the internet, the new install will activate. You do not need a product key.

It is my understanding that Windows 10 skips certain steps during boot that previous operating system preformed. This allows for a faster boot time. You can still instruct Windows 10 to preform these skipped steps at the cost of speed. I don't know what happens when upgrading from Windows 7.

I first upgraded from Windows 8.1 which did allow me to active Windows 10, but I had enough problems with the upgrade that it was worth doing a clean install. I did not use the Boot Camp Assistant.

Windows is using a legacy BIOS boot. I doubt my computer would support an EFI boot of Windows. Although, I can boot Ubuntu (linux) using EFI without any problems.


the 'trick' is to do a clean Win10 install with an an USB Stick made from the MS Win10 Media creation tool, BUT for the first but, you need to press the Option key and choose the native USB Stick and not the legacy (you should see 3 options: MacOS EFI, USB EFI and USB Bios but symbols, no text)

Win10 installs extremely fast in 20 Minutes. AND the boot time is reduced from 15 seconds to 1-2.

The BootCamp Assistant USB Stick, which does not support EFI Boot, at least in my case with 2011 MBA, is needed for the post installation work.

But: as of Sept. 21 there was no working video driver from intel, screen keeps getting dark, and Windows Update also forces download and install of that bogus driver. be carefull.

for me only the generic video driver worked, but does not support any standby/suspend modes and no sound.

what DOES work: install Win10 in non GPT BIOS/legacy mode, for some reasons(???) the video driver then works and the rest and only this annoying BIOS Wait time even after hibernate.

  • it turns out to be a big mess. :( there are no Intel video drivers that support MBA despite the MS generic ones. And as long as there are no video drivers, there is no Standby, suspend, no sound etc. And booting is like gambling. no fun at all. from the current point of view, it's more than a waste of time, because the time i spent is much more than waiting 1000 times in BIOS mode for 15 sec – Falco Alexander Sep 21 '15 at 21:51

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