driver-api/firmware/fallback-mechanisms.rst

207 EFI embedded firmware fallback mechanism
210 On some devices the system's EFI code / ROM may contain an embedded copy
225 The EFI embedded-fw code works by scanning all EFI_BOOT_SERVICES_CODE memory
234 To register this array with the efi-embedded-fw code, a driver needs to:
243    drivers/firmware/efi/embedded-firmware.c wrapped in a #ifdef testing that
249 with the specified name directly from the disk, so the EFI embedded-fw can
254 1. The code scanning for EFI embedded-firmware runs near the end
258    embedded-firmware.
260 2. At the moment the EFI embedded-fw code assumes that firmwares always start at
264 3. At the moment the EFI embedded-fw code only works on x86 because other archs
265    free EFI_BOOT_SERVICES_CODE before the EFI embedded-fw code gets a chance to
278 Example how to check for and extract embedded firmware
281 To check for, for example Silead touchscreen controller embedded firmware,