Batocera builds RetroArch with its core downloader (configure defaults,
qb/config.params.sh:149-150), shown in the menu since it is no Lakka
build (config.def.h:743-745), and configgen sets no URL, so the compiled
one applies: buildbot linux/x86_64 or linux/armhf, none on aarch64
(config.def.h:1855-1861). The targets scraper names that list per board
(downloads, an armv7-A CPU read from arch/Config.in.arm), the builder
and the published target lists add it, and the platform names the union
as installable_cores. applewin, gong, squirreljme and vemulator come
back that way. A build option that compiles the downloader out, or a
shipped retroarch.cfg that blanks its URL, turns it off.
No Batocera board turns on BATOCERA_CORES_STILL_COMMERCIALIZED or
BATOCERA_CORES_EXPERIMENTAL (Config.in:109, 1670), so citron, ryujinx,
applewin and eka2l1 are not built, and freej2me, gong, squirreljme, uqm
and vemulator are selected by no Kconfig file at batocera-43.1. Read
with every sourced Kconfig file, the Pi 4 boards gain dxx-rebirth,
sonic2013, soniccd and xroar (mesa3d-rpi4 gives them OpenGL).
Batocera and KNULLI write the image name, not the board, to the card's board file (post-image-script.sh). The target scraper now records each board's images from Config.in, the target lists carry them, and the installer maps a card's image to its board. KNULLI's boot/knulli.board is read too.
Continued if-conditions were cut at their first line, so GLES3 held on every board, and selects guarded by a negation stayed on once fired. Derived flags are read line by line, each pass rebuilds the symbol set from the board, and the architecture comes from the board's BR2_<arch> choice.
Abdessamad Derraz