Thanks for your guidance.ok. Yes Get twrp reinstalled first .
How I install the rom while in twrp is I copy the zip file to SD card. and also you should have a copy of super su .
Now take that micro SD card and insert it into your fire .
Reboot . while in twrp recovery
Go to wipe , select data
Now choose switch file system to ext2 , select format. use right bar button swipe to complete.
Hit back button , now select ext4 . format in xt4 format.
Hit back bottom .
Now go to install . select from bottom right of menu , install zip from,
select your external SD card from the menu .
choose the ROM file zip.
Select install .
When done , now go back ,select super su and install .
I would try to install ROM this way from micro SD card once you did the procedure to
Flash twrp .
Unfortuantely the first step in installing TWRP -- sudo ./bootrom-step.sh -- keeps giving me the same error. It gets to "Clear preloader header" and then keeps failing with the same error message (attached).
This same script worked earlier, but since that inital success has always given me errors. Is this expected? Should I just keep re-trying?