MacBook Pro 2011: unable to get into terminal via Recovery Mode [duplicate]

I have a MacBook Pro 2011 with the well known AMD GPU failure. So I know about the procedure to de-activate the AMD GPU and activate the Intel GPU on the mainboard. This has to be done via the command line in Terminal, for which you need to start Recovery Mode and get into OSX Utilities and then start Terminal.

Unfortunately, booting in Recovery mode ends before I get into OSX Utilities. The screen goes grey and then either shuts the system down, or it starts rebooting.

The MacBook is currently installed with High Sierra.

What can I best do?

I'm trying to find a way to avoid getting into graphics mode. I remember in the olden days displays had a command line mode and graphics mode.

(1) I'd try single use mode. This page will tell you how to get into single user mode. http://support.apple.com/kb/HT1492

Basically, you hold down the command + s key then power on your machine. [ The command key has a little apple symbol on the lower left. It is between the alt/option key and the space bar. ]

(2) You could try safe mode. This avoids using the graphics hardware. Try a safe boot. Shutdown your machine. Hold down the shift key. Poweron. The boot up will take longer than normal because the filesystem on the startup drive is being checked and repaired as needed. All about safe mode including what features and apps safe boot leaves out. Safe boot uses a software driver instead of using your machines video hardware. http://support.apple.com/kb/ht1455