I bought a pi4 a+ andflashed 3 different os with balena etcher on both usb flash and sd card.
Results:
Debian 11.4 netinst: green led continously light and black screen
Manjaro 22.06 xfce: green led continously light and black screen on display
armbian 22.05.4: green led continously light + blue led blinking and black screen on display (no signal at all)
How do i make this work? can you tell me how step by step because i’m a newbie
Ok after lots of read and rest, i’m come closer to make maskrom remove process.
But given RKDevTool 2.81 is chinese. I cant read chinese with all my respect. And does rkdevtool contain loader and image file and their entries on rkdevtool?Yeah too many question 
Well, i converted the app English (config file edited and Selected=1 made 2)
Then short circuited spi pins as shown in photo.
Then maskrom button pressed and powered up.
Result No devices Found.
Maybe because i used type c to type A cable. I wşll order type A cable. Then update the thread.
I have a raspberry pi also and it is a breeze. It doesnt need such things, it almost plug and play as a windows.
USB type C to A is a known issue. However I have the same problem. My keyboard lights go on, the mouse light goes on, but video is going to a signal and then no signal all the time. It seems like it is in some kind of boot loop. Are your mouse and keyboard responding at all (lights and such?)
Keyboard didn’t responding. Mouse, i didn’t plug in. I’m all for this https://wiki.radxa.com/Rockpi4/dev/usb-install