Sierra NetBoot Image Kernel Cache Too Large, Startup Fails

Originator:ferguspa
Number:rdar://28432978 Date Originated:9/22/2016
Status:Open Resolved:
Product:macOS Product Version:macOS 10.12.0 16A323
Classification:Serious Bug Reproducible:Always
 
Description
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After making the modification to createNetboot.sh detailed in rdar://28426901 (increasing cacheSize from 1300 to 2000), the resulting NetBoot image's "kernelcache" file is 67.5 MB.  This file is too large to send to some computer models' EFI TFTP clients.  This causes some computers supported by Sierra to be unable to NetBoot Sierra.

Steps to Reproduce
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1) Modify createNetboot.sh as detailed in rdar://28426901 ( http://www.openradar.me/radar?id=6136092554166272 )
2) Create a NetBoot image
3) Add the NetBoot image to a NetBoot server
4) Boot a computer (my test computer is a Late 2011 13" MacBook Pro) from the Sierra NetBoot image

Expected Results
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The computer NetBoots normally.

Actual Results
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The computer goes from:

- Flashing globe
- Apple with spinning globe
- Prohibitory symbol

This set of steps cycles a few times and then the computer fails back to starting from the local disk.

Configuration
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Late 2011 MacBook Pro booting from a macOS 10.12.0 16A323 Sierra NetBoot image.

Other computers (such as a blank VMware Fusion 8.5 VM and a Late 2012 21.5" iMac) NetBoot properly from the same NetBoot image.

macOS Version/Build
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macOS Sierra 10.12 16A323

Additional Notes
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This was an issue in 10.9.3 and was fixed in 10.9.4.  Discussion about this bug in 10.9.3 occurred here:

https://jamfnation.jamfsoftware.com/discussion.html?id=9836

Comments


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