In this video, several Chinese Game Boy bootlegs have a secret option to access the main device test. To see the main device test by pressing Y (as B) + B (as A) buttons by power it on or pressing the reset button when the unit is on.
Handhelds:
1. Wanle D-12 Game Power (Power Bank with 416 Games)
2. Game Box 800 in 1 (The box is similar as 500 in 1 in 300 games).
3. Sup Game Box 168 in 1 (in PCB board, it later replaced by i50 999 in 1 Game Boy)
4. Sup Game Box 400 in 1 (reversed duty cycle audio)
![](https://s2.save4k.ru/pic/4cfwqwBgJxQ/mqdefault.jpg)