Have a situation here.
my device recently returned from repairs (dropped my HTC and broke the screen

). after return my device was 'locked' and a 'freshly' mint device again. Now i want to install the most recent TWRP version - preferably first by boot command so i can make a clean nandroid BCK of my device - and afterwards by flashing TWRP and this is what i am facing and yes i did unlock the device at HTCDEV site.
By boot command: black screen and apparently no respond anymore on the hardware keys, but still responding by fastboot command "reboot bootloader" and while
By flash command i received an error message in the language of: cant flash a "PRODUCTION" model.
anybody ever heard of this and more important does have a solution for this problem?
awaiting any response.