fastboot boot TWRP.img Not working I'm trying to just boot the TWRP image for my OnePlus 5t to then install a custom ROM. So I typed fastboot boot "C:\Users\Elias\Downloads\twrp-3.3.1-0-dumpling.img" and it seemed to work and I got the output:

Downloading 'boot.img'                             OKAY [  0.808s]
booting                                            OKAY [ 10.119s]
Finished. Total time: 10.992s


But the device just shows the text: "Fastboot Mode" and doesn't do anything.
I now read on this forum that they somehow removed it but it would still be possible with: fastboot -c "lge.kcal=0|0|0|x" boot customrecovery.img
 but this flag doesn't seem to exist. 

The output is:

C:\platform-tools\fastboot.exe: unknown option -- c


My goal is just to install a custom ROM without actually flashing anything except the ROM. So if somebody knows a different way, it would be welcome as well.
There are different versions of fastboot.exe available. 

One old version I have has the command line option -c as 

-c &lt;cmdline&gt;               override kernel commandline


The recent versions for Android SDK (v29.0.5-5949299) does not has the -c option. Instead it has the option --cmdline which seem to the the exactly same thing:

--cmdline CMDLINE          Override kernel command line.


Therefore you may succeed changing the command-line to

fastboot --cmdline "lge.kcal=0|0|0|x" boot customrecovery.img