<< Solved >> 10.14.5/2 fails to boot from USB (xid 1520)

[1amBulletproof]

Did you physically remove it or simply remove the power cables?

 

[tk3]

Both. Totally took it out of the case. Might be overkill, but oh well.

 

[tk3]

Update: Mojave boots okay without GPUs installed. It gets about halfway through the Mac load screen, drops monitor signal (via iGPU over HDMI), then the login screen pops up about a minute later and everything works fine.

Then when I try to boot with GPUs installed (XFX RX 580 GTS Black Edition), it kernel panics.

So I think my course of action is to 1) try to boot with RadeonDeInit in Clover, 2) try to boot with and alternate vBIOS injected via Clover and, if neither of those work, 3) flash the vBIOS on the card with a Sapphire vBIOS.


Open to additional suggestions of fixes, but seems the most likely culprit an incompatibility with the BIOS on the XFX GPU.


Also, any thoughts on how to fix the minute of black screen while booting from iGPU?

 

[1amBulletproof]

Update: Mojave boots okay without GPUs installed. It gets about halfway through the Mac load screen, drops monitor signal (via iGPU over HDMI), then the login screen pops up about a minute later and everything works fine.

Then when I try to boot with GPUs installed (XFX RX 580 GTS Black Edition), it kernel panics.

So I think my course of action is to 1) try to boot with RadeonDeInit in Clover, 2) try to boot with and alternate vBIOS injected via Clover and, if neither of those work, 3) flash the vBIOS on the card with a Sapphire vBIOS.


Open to additional suggestions of fixes, but seems the most likely culprit an incompatibility with the BIOS on the XFX GPU.


Also, any thoughts on how to fix the minute of black screen while booting from iGPU?

fascinating. I have an issue with a radeon 590 where my signal drops halfway through the boot process. my monitor literally says no display signal. perhaps i should wait some significant amount of time to see if it comes back!?

also i’m getting an rx 580 sapphire in and we will see if that works any better. it seems like the exact version of 580 matters....

 

[tk3]

Flashed the XFX 580 with a Sapphire RX 580 Pulse vBIOS and it didn't kernel panic ... but did boot to black screen. so now to figure that one out.