cerf.json - the configuration files

There are three layers of JSON configuration files:

#	File	Where	Meaning
1	cerf.json	next to cerf.exe	packed in the release
2	cerf.json	devices/<name>/	a configuration of your device
3	cerf-user.json	devices/<name>/	same, but stores only overrides by user

CERF applies each layer on top of the previous one, key by key. CERF applies the command line last, so a flag always wins over a file.

global cerf.json  ->  devices/<name>/cerf.json  ->  devices/<name>/cerf-user.json  ->  command line

Later wins. Below is an unfinished description of schema. Some values are absent from here.

Layer 1 - the global cerf.json

Key	Type	Meaning/values
device	string	The device directory to boot when the command line has no --device=
bundle_repositories	array of { url, enabled }	The ROM bundle repositories
last_save_state_mode	boolean	Save the state checkmark state in shutdown window
update_channel	string	disabled, stable, or unstable.
discord_rich_presence	boolean	-
tutorial_finished	boolean	-
host_key	integer, or array of integers	One VK or max 8 VKs. Absent: Right Ctrl (163).
default_scale	integer	Integer scaling at start. 0 (Dynamic), 1 (Original view), 2, 3, or 5. Absent: 0.
host_branch	string	win32-x86, linux-amd64, linux-arm64, macos-arm64, android-arm64, android-amd64. Reserved: windows-amd64, windows-arm64. Absent: win32-x86.

Layer 2 - the device cerf.json

board

Key	Type	Meaning/values
id	string	the board ID cerf emulates from db.json
configurable_screen_width	integer	device models a panel with dynamic resolution - width
configurable_screen_height	integer	as above
configurable_screen_dpi	integer	as above
configurable_screen_bpp	integer	as above

rom

Devices define their own keys since sources may vary accross devices. Here are some generic but not all:

Key	Type	Meaning/values
primary	string	a generic ROM path if a device support it. Most of devices share this key
recovery	string	alternative to primary but boots with --recovery (FIXME: wait, i thought i removed it)
eeprom	string	Used for devices which have one EEPROM dump
lumia800_user_area_erase	string	Lumia 800 specific firmware package file

storage

Identical conception as above but for writable persistant user storage.

Key	Type	Meaning
nand	string	A NAND flash image, relative to the device directory. Absent, nand.img.
hdd	string	A hard disk image, relative to the device directory. Absent, hdd.img.
emmc	string	An eMMC image, relative to the device directory. Absent, emmc.img.

Network

Key	Type	Meaning
network.enabled	boolean	The same as --disable-network inverted.
network.mac	string	The guest MAC, XX:XX:XX:XX:XX:XX. (FIXME: there can be one MAC per a network device and CERF lets you to use several at once. Do we increment the MAC or something? I forgot)
network.mtu	integer	64 to 1500.
network.forward_tcp, network.forward_udp	string	Host-to-guest port forwards. I don't know if it still works, nobody tested it since CERF v1

Guest Additions

Key	Type	Meaning
guest_additions.enabled	boolean	The same as --guest-additions.
guest_additions.override_color_scheme	string	The same as --ga-color-scheme.
guest_additions.override_font_size	integer	same as --ga-font-size.
guest_additions.override_cleartype	boolean	-
guest_additions.allow_untrusted_apps	boolean	-
guest_additions.indexed_palette	array of [r, g, b]	Palette for 1, 2, 4 or 8 bpp. Absent: Auto.
guest_additions.share_folder	string	The same as --ga-share-folder.
guest_additions.shared_folder_mount_point	string	-
guest_additions.autorun	array of strings	Guest paths. When the shell is up, the guest driver starts each path, in order. --ga-autorun=PATH replaces the array. (FIXME: should we add this to UI?)

Rest

Key	Type	Meaning
full_screen	boolean	-
double_tap_helper	boolean	A double tap at single coordinate helper for Android
throttle_multiplier	number	-
cpu_rate_multiplier	number	-
hud	string	none, or a HUD id from huds.json. Absent: the HUD of the board.
additional_packages.compact_flash_cards	array of { file, name, insert_on_launch }	CF cards from a ROM bundle that are displayed in UI and might be auto-attached at launch
meta	object	Who the device is: name, device_name, and os (name, ver_major, ver_minor). Pure metadata.

Layer 3 - cerf-user.json

Identical to cerf.json. Conception is that cerf.json is a ROM bundle's one that changes only on ROM bundle updates, and cerf-user.json is where you dump all your personal overrides. Second is applied over first. Your data is never lost on ROM bundle updates.