Boot from Recover Mode with USB Thumb Drive and External Monitor

[RedBeardCrew]

I have a weird problem I need solved. I have a Mid 2011 27” iMac that I upgraded to an internal SSD rather than a HDD. I accidentally placed the display cable back into the logic board backwards and fried that circuit so the monitor won’t work. I know, dumb, I couldn’t see a difference and it was hard to see which way it went back on while sticking my hand in there to reconnect it. Now I need to boot from a recovery file I put on a USB thumb drive for MacOS but the external display I have plugged into a DP/thunderbolt to HDMI convertor won’t read and work as the display on bootup into recovery mode. Have tried booting into every recocery mode I could find instructions for online (internet recovery cmd+opt+R, regular recovery cmd+R, and choosing a recover device holding opt) but can’t get the external display to work. Hit cmd+F1 and holding “m” don’t work to put it into mirror mode. Anyone know how to boot simultaneously into recovery mode and external display mode at the same time?

 

[Fishrrman]

When you have a bootable USB flashdrive, you are NOT booting into "recovery mode".

You are booting FROM the flashdrive.

1. Power off
2. Press the power on key
3. IMMEDIATELY hold down the option key and KEEP HOLDING IT DOWN until the startup manager appears
4. Select the USB flashdrive with the pointer and hit return.
5. Mac should boot from the flashdrive.

But... not sure if this will work with a broken internal display and external monitor.
Might be time to take the internal HDD out and... call it quits on the iMac.