Cant create a boot usb or netboot to image on iMac (Retina 5K, 27-inch, 2017) Model Identifier: iMac18,3

[NealIV]

Anyone else having this issue? I have the latest 10.12.5 mac OS along with the macosupd10.2.5 patch but no go.

[davidacland]

I'm pretty sure that model has it's own forked version of 10.12 so the dmg would need to be captured directly from it.

[ega]

Even if that is not the case, I can't create working 10.12.4 or 10.12.6 NetInstall due to getting signing errors on install which is a known issue with Apple.

[ega]

Even if that is not the case, I can't create working 10.12.4 or 10.12.5 NetInstall due to getting signing errors on install which is a known issue with Apple.

[apizz]

We are as well - although we haven't tried with the new iMacs yet - we are having a lot of difficulty imaging with a Netboot image running macOS 10.12.5.

Rather than block copying our OS DMG file, it unmounts the drive, says its block copying and then a few seconds later says it's finishing block copying.

[mcarver · Accepted solution]

You have a forked macOS issue. Best option is to wait until 10.12.6 is released and build off it. These are 2 sites that are good to have bookmarked: https://support.apple.com/en-us/HT201260 and https://support.apple.com/en-us/HT204319. They should you the OS and build that is shipped with each model and what builds the App store releases.

[cbrewer]

Read here

[techmchs]

literally just finished building the forked image and NBI as above yesterday (thanks to everyone on forums!:) now today 10.12.6 dropped.. any verification that this gets rid of the need to create forked boot NBI and image?

[techmchs]

double post

[apizz]

@techmchs I'm building a base OS with the 10.12.6 installer now to test with Netboot. I'll report once it's done and I've tried imaging.

[apizz]

While this may work for folks, I'm still experiencing the issue I mentioned in my previous post where the OS DMG file is not block copied.