Hello I am new to this but after hours of troubleshooting I was able to get my RIP 7in to work. I first downloaded an image from https://github.com/radxa/rock-pi-images-released/releases. I then went ahead and edited the /boot/hw_intfc.conf file. I changed intfc:i2c2=on, intfc:i2c6=on, intfc:i2c7=on. I then uncommented the line "intfc:dtoverlay=raspberrypi-7-inch-lcd. From there along with the 5v and ground pins I plugged in the SDA and SCL. SDA into GPIO 3 and SCL into GIPO 5. Note you will need to reboot your system after editing the .conf file. Hope this helps!