Safe Mode hangs at "PCI Configuration Begin"

[Iconoplasty]

I'm trying to boot my Sierra box into Safe Mode (a suggestion to try to fix a problem caused at the latest update to 10.12.6). Unfortunately, the boot process is hanging at "PCI Configuration Begin" (I'm booting "-x -v" so I can see boot progress). I've done some searching and found a little advice, but unfortunately, nothing that has helped yet.

I'm using a Core i7 3.4GHz with an ASUS X99-A II motherboard.

At the point where the boot appears to hang, the drive light keeps flashing as if the boot process is continuing. On the off chance this is a graphics driver issue I tried booting alternately with "nc_disable=1" and "nvda_drv=1". Neither option helped.

Everything I've been able to find on Tonymac seems to be related to hangs at regular boot (not safe mode) and/or the initial OS install. By default the clover config already uses "npci=0x2000" so I've tried changing that to "0x3000", and I've tried both of those with and without "-no-zp". Nothing has changed the behaviour at boot.

Are there other things I should be trying?

 

[Wenatchee]

I'm having the same problem too. I've tried a myriad of different boot flags with no results. Have you had any luck getting Safe Mode to boot yet?

 

[BreBo]

@Wenatchee, please update your profile (account details) with your Motherboard, CPU and iGPU or Graphics Card(s).
If you have a prebuilt computer enter make and model instead of motherboard.

Profiles are mandatory so that others can assist you.