Which firmware type should I use?
Check the type according to your device:

Device	Firmware type
Retro Game v1.0	Type 1A
Retro Game v1.0 S	Type 1A or Type 1B
Retro Game v2.0	Type 2A
Retro Game v2.1	Type 2A or Type 2B
Retro Game v3.0	Type 3B
Retro Game Plus (60Hz)	Type 3B
Retro Game 300	Type 3B or Type 2B
Retro Game 300 IPS	Type 5B
Retro Game Plus Anniversary	Type 5B
Retro Game Plus IPS	Type 5B
Retro Arcade 4.3v1.3	Type 4B
LDK (Horizontal)	Type 2A
LDK (Square)	Type 2B
And the devices according to the firmware type:

Firmware type	SoC	Screen Module	Device
Type 1A	JZ4760	AUO A030JTN01 320x480	Retro Game v1.0, Retro Game v2.0, Retro Game v1.0 S
Type 1B	JZ4760B	AUO A030JTN01 320x480	RetroGame v1.0 S
Type 2A	JZ4760	INNOLUX EJ030NA-01B 320x480	RetroGame v2.1, LDK (Horizontal)
Type 2B	JZ4760B	INNOLUX EJ030NA-01B 320x480	Retro Game v2.1 B, Retro Game v3.0 B, LDK (Square), Retro Game 300
Type 3B	JZ4760B	LianKeWeiYe LKWY030A01 320x480	Retro Game v3.0 B, Retro Game Plus (60Hz), Retro Game 300
Type 4B	JZ4760B	Samsung LTP400WQF02 480x272	Retro Arcade 4.3v1.3
Type 5B	JZ4760B	Tony's custom Sharp IPS 320x480	Retro Game Plus Anniversary Edition, RG300 IPS, Retro Game+ IPS