PS4 Testing Kit on 6.20 Firmware Debug Settings Overview by MrNiato : r/ps4homebrew
Payload 6.72 and 505 ToDEX to unlock some debug functions
Team SGK - PS4 Playground Updated by Fx0day with PlayStation 4 FTP & Debug Mode Today PlayStation 4 developer fx0day added the PS4 Debug Mode and a PS4 FTP Server to the
Debug PS4 unboxed for your viewing pleasure – Destructoid