X7 Handheld Firmware [best] Link

What I liked

Optimized kernels allow smoother gameplay on systems like GBA, NES, SNES, and PS1. x7 handheld firmware

Ensure your X7 handheld is charged to at least 80% to prevent the console from dying mid-flash. What I liked Optimized kernels allow smoother gameplay

This indicates a display driver mismatch within the firmware. The OS is running, but it cannot communicate properly with your specific LCD screen panel. You will need to source a firmware variant that specifically mentions support for your screen type. x7 handheld firmware