Install Windows 10 64 bit on iMac 7.1 Early 2007 or how to make your old Mac usefull again

As title says it I was given the task to resurrect an iMac and put it back in business! 🙂

Unlike Microsoft, Apple are very picky on how you gonna use your computer and are unpleasantly pushy on dragging you to buy more of their stuff. Simply said as some of you may already know you can not use old, but quite descent hardware wise Mac with Apple’s latest OS due to firmware restrictions. Luckily you can still make some use of it with Windows or Linux.

The iMac in question had a faulty hard drive, which luckily was not too difficult to replace. But as usual the troubles came soon after! 🙂

With a freshly burned DVD with Windows 10 x64 a thought I will be quickly in the game, but NO – got stuck with a black screen and a message to pick the boot type and irresponsive keyboard! It turns out though the computer is 64 bit architecture its EFI is 32 bit and you have no chance to boot it from Windows 10 installation media…

Thanks to good and clever people online help is available! I read this post, downloaded the exe file provided and it all went well!

As the steps I took are slightly different I wanted to have a note of it.

First of course you will need the Windows 10 x64 image file, which you can download from Microsoft. Under Windows 10 with right click on the file select “Mount”.

Just to make life organised create a folder with a name of your choice, in my case it was “NewISO”.

Run Command Prompt as administrator and navigate to where you have the OSCDIMG.EXE file saved /or just type the full path to it/.

Then run the command:

oscdimg -n -m -bf:\boot\etfsboot.com f:\ c:\NewISO\win10_efi32.iso

where f is the drive letter where the image file is mounted.

After this you will have e 64 bit Windows 10 image file with 32 bit EFI, do not worry about the warning message related to NT 3.5, just burn it on DVD or USB stick and use it.

Final words – I do not quite know how this program, which is a Microsoft genuine tool, manages to change the boot loader. I would advice you to download it from the post link above or at least make sure you use the same version, which is 2.54, as this may have something to do with the success of the procedure and a newer one may just put back 64 bit EFI again. I will be glad if someone more knowledgeable explains it in detail.

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