The MiST/SiDi firmware has a few configuration options available, which can be set by adding a "mist.ini" file to the root of the SD card.

Overall the file should contain a "mist" tag at the top:

[mist]
usb_storage=0                  ; set to 1 to allow accessing the SD Card via the USB port (only for Linux, SiDi FS, SiDi128 HS)
joystick_db9_md=0              ; 0 - MegaDrive pad disabled, 1 - enabled, 2 - auto-detect after reset (only for SiDi128)
csync_disable=0                ; set to 1 to output separate hsync and vsync in 15kHz
keyrah_mode=0
scandoubler_disable=0          ; set to 1 to run supported cores in 15kHz
mouse_boot_mode=0              ; set to 1 if a mouse does not work well
joystick_disable_swap=0        ; set to to disable the automatic swapping of joystick 0 and joystick 1
joystick_emu_fixed_index=0     ; set to 1 for always emulating the first two joystick via keyboard
joystick_autofire_combo=0      ; set to 0 for LCTRL+LALT+KP0, 1 for LCTRL+LALT+TAB, 2 for disable autofire toggle
joystick_dead_range=4          ; set to 0 to disable analogue joystick dead range (useful for paddles)
joystick_ignore_hat=0          ; set to 1 if having issues on gamepads with 'POV hat'
joystick_ignore_osd=0
joystick_disable_shortcuts=0   ; set to 1 to remove joystick -> keyboard commands 
joystick0_prefer_db9=0
mouse_speed=100                ; set to scale mouse speed (in percentage, default is 100%)
key_menu_as_rgui=0
reset_combo=0
ypbpr=0
keep_video_mode=0
led_animation=0
key_remap=
key_remap=
hid_button_remap=
joystick_remap=
joy_key_map=
[c16]
rom=1541KRNL
rom=KERNAL

Comments can be added after each setting by using ; e.g.:

[mist]
scandoubler_disable=0 ; leave at 0 if not sure
...

If set to 1, some cores will disable their scandoubler to produce a 15khz video signal. This works better for upscalers and arcade displays. Also if you want to use a VGA-to-SCART cable with MiST, you need to set this option to 1.

Support is core specific; currently it is used by the ST, Amiga, Colecovision, Vic20 and Astrocade and several other cores. Cores not supporting this will ignore the setting.

For more details see Scart cable.

Joystick remapping allows to rearrange the joystick/gamepad buttons. More information can be found here.

If set to 1, some cores will enable component (YPbPr) video output. For more details see YPbPr/RGsB cable.

If set to 1, YPbPr and/or Scandoubler modes will be preserved between cores till reset button is pressed (either on MiST board, or hard reset key combination).

Choose key combination for reset:

0 - LCtrl-LAlt-RAlt
1 - LCtrl-LGui-RGui (Ctrl-LAmiga-RAmiga)
2 - LCtrl-LAlt-Delete

If set to 0 then keyrah v2 converter will have special tweaks for convenient usage in Minimig and other cores. Please note it requires ISO US/UK type of keyboard (with two blank keys). For ANSI and localized keyboards set this option to 1 to disable all keyrah tweaks.

Set to 1 to revert back to an old mouse handler which may solve compatibility issues with some mice (the default handler is much more compatible with keyboard/mouse wireless devices, though).

If set to 1, the firmware will revert to old behavior of using analog axes instead of the digital direction pad, which is the default behaviour for newer firmwares (since firmware_150524).

This allows you to remap USB HID keycodes reported to the cores. For example, if you want to exchange the keys 'a' and 'b' on your keyboard you'd want to have the USB HID keycodes 04 (the USB Usage ID of the key labeled 'a') and 05 to be exchanged the mist.ini would look like:

[mist]
key_remap=04,05
key_remap=05,04

This makes key 04 to be reported as key 05 and vice versa.

Most cores allow to upload a default rom named <corename>.rom. For some cores like the c16 core this file includes several rom files. In case of the c16 this file e.g. includes the 16 kBytes floppy rom, the 16 kBytes kernal rom and the 16 kBytes basic rom. These are usually only available as seperate files and the user would have to combine them into one file for MIST upload.

The rom option allows to specify several file names for upload like so:

[c16]
rom=1541KRNL
rom=KERNAL

In this case a file named 1541KRNL.ROM and a file named KERNAL.ROM are uploaded. The files names must be short (max 8 characters) and they must only consist of uppercase letters and numbers. Also the .ROM extension is not explicitely specified in the ini file but appended automaticallc. The example above would load the 16 kBtyes 1541KRNL.ROM file and the 16 kBytes KERNAL.ROM file whenever the c16 core is being loaded.

Roms are uploaded in the order they appear in the ini file. The rom option should always be used in the "per core settings" as described below since the ROMs are highly core specific.

Each core may need some different settings like key remap or scandoubler enable/disable. Any option from "mist" section can be overridden for specific core. Just add another section with core name and new value for desired setting. Hardcoded names for specific cores: MINIMIG, ST, PACE, ARCHIE. For 8bit cores use names you see on main page of OSD on the left vertical stripe.

example:

[minimig]
scandoubler_disable=1

"mist" section should be the first section in INI!