Miyoo Mini¶

Miyoo Mini

Links¶

Emulators, Ports and Applications¶

System¶

Hardware¶

Official store in Aliexpress
UART mod:
- steward-fu
- eduardofilo
Teardown
3D Print:
- More accessible triggers: V1, V2
Spare parts

Firmware's rootfs mounting¶

Download the file used to update the console firmware from official site.
Locate inside the ZIP the .img file. In the case of the 2022-04-19 update the file is located in The firmware0419 directory and is named myoo283_fw.img.
Open the file with an hex editor to read the beginning of it which contains information in text form with the blocks inside the image and where they are flashed on the NAND. In particular we are interested in the section describing the rootfs partition which contains the following information:
```
# File Partition: rootfs
mxp r.info rootfs
sf probe 0
sf erase ${sf_part_start} ${sf_part_size}
fatload mmc 0 0x21000000 $(SdUpgradeImage) 0x1ae000 0x22b000
sf write 0x21000000 ${sf_part_start} 0x1AE000
```
According to the U-boot fatload command documentation, the last two parameters in hexadecimal are the size and the position of the rootfs partition inside the .img file.
Create a directory (for example mnt) and run the following command to mount the firmware rootfs in it:
```
sudo mount -o loop,sizelimit=0x1ae000,offset=0x22b000,ro,noexec miyoo283_fw.img mnt
```

Using the same method you can also mount the miservice and customer partitions:

sudo mount -o loop,sizelimit=0x32f000,offset=0x3d9000,ro,noexec miyoo283_fw.img mnt2
sudo mount -o loop,sizelimit=0x6c5000,offset=0x708000,ro,noexec miyoo283_fw.img mnt3

Cheatsheets¶

Interesting firmware directories/files¶

Directory	Content
`/mnt/SDCARD`	SD mounting point
`/customer/main`	Main frontend startup script. It is the one that invokes `.tmp_update/updater` in case it exists which is the starting point of UIs like Onion or MiniUI
`/sys/devices/gpiochip0/gpio/gpio59/value`	Flag indicating if the machine is being charged
`/sys/class/pwm/pwmchip0/pwm0/duty_cycle`	Screen brightness (from 0 to 100)
`/sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors`	Available governors for processor (`userspace`, `powersave`, `ondemand`, `performance`)
`/sys/devices/system/cpu/cpufreq/policy0/scaling_governor`	Current governor
`/sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies`	Available frequencies for processor (`400000`, `600000`, `800000`, `1000000`, `1100000`, `1200000`)
`/sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq`	Minimum frequency for processor
`/sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq`	Maximum frecuency for processor
`/sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq`	Current frecuency
`/appconfigs/system.json`	System general settings (corresponds to Settings menu)

Interesting OnionUI directories/files¶

Directory	Content
`/mnt/SDCARD/Saves/CurrentProfile/saves/playActivity.db`	Play Activity database. To reset the statistics, you can simply delete the file
`/mnt/SDCARD/Saves/CurrentProfile/saves/PlayActivityBackup/`	Directory containing backups of the previous `playActivity.db` file. Apparently this directory is not purged, so you will have to do it by hand from time to time.
`/mnt/SDCARD/Roms/recentlist.json`	`Recent` list
`/mnt/SDCARD/.tmp_update/romScreens/`	Screenshots
`/mnt/SDCARD/.tmp_update/.disableMenu`	Disables the Game Switcher associated with the Menu key

GPIOs¶

/ # cat /sys/kernel/debug/gpio
gpiochip0: GPIOs 0-90, gpio:
 gpio-1   (                    |GPIO Key Up         ) in  hi
 gpio-5   (                    |GPIO Key Right      ) in  hi
 gpio-6   (                    |GPIO Key B          ) in  hi
 gpio-7   (                    |GPIO Key Y          ) in  hi
 gpio-8   (                    |GPIO Key A          ) in  hi
 gpio-9   (                    |GPIO Key X          ) in  hi
 gpio-10  (                    |GPIO Key START      ) in  hi
 gpio-11  (                    |GPIO Key SELECT     ) in  hi
 gpio-12  (                    |GPIO Key MENU       ) in  hi
 gpio-13  (                    |GPIO Key L          ) in  hi
 gpio-14  (                    |GPIO Key L2         ) in  hi
 gpio-47  (                    |GPIO Key R2         ) in  hi
 gpio-59  (                    |sysfs               ) in  lo
 gpio-69  (                    |GPIO Key Down       ) in  hi
 gpio-70  (                    |GPIO Key Left       ) in  hi
 gpio-72  (                    |                    ) out lo
 gpio-86  (                    |GPIO Key POWER      ) in  lo
 gpio-90  (                    |GPIO Key R          ) in  hi

Keys¶

Key	GPIO	SDL value	SDL descriptor
Up	1	273	SDLK_UP
Down	69	274	SDLK_DOWN
Left	70	276	SDLK_LEFT
Right	5	275	SDLK_RIGHT
Menu	12	27	SDLK_ESCAPE
A	8	32	SDLK_SPACE
B	6	306	SDLK_LCTRL
X	9	304	SDLK_LSHIFT
Y	7	308	SDLK_LALT
Select	11	305	SDLK_RCTRL
Start	10	13	SDLK_RETURN
L1	13	101	SDLK_e
L2	14	9	SDLK_TAB
R1	90	116	SDLK_t
R2	47	8	SDLK_BACKSPACE

Framebuffer¶

/ # fbset

mode "640x480-100"
        # D: 45.455 MHz, H: 54.633 kHz, V: 100.060 Hz
        geometry 640 480 640 1440 32
        timings 22000 64 64 32 32 64 2
        accel false
        rgba 8/16,8/8,8/0,8/24
endmode

The frambuffer (/dev/fb0) contains 3 images (640x1440) and is rotated 180º. Each pixel occupies 4 bytes encoded in the following order: BBGGRRAA where AA (alpha) is always FF.