Embedded Linux build systems

Buildroot

• use an external layer, don't forget to set the env variable before make my_defconfig
• build images with genimage and sign in post-image.sh
• generate configs image with in-fakeroot.sh (why? I don't remember)
• create patches with quilt
• can have multiple rootfs_overlays, use a common base for multiple boards

override built-in package build steps in external.mk

# Strongswan TPM2 support
#STRONGSWAN_CONF_OPTS += \
#   --enable-tss-tss2=yes \
#   --enable-tpm=yes \

#STRONGSWAN_DEPENDENCIES += tpm2-tss tpm2-abrmd

# Start TPM2 abrmd before Strongswan
define TPM2_ABRMD_INSTALL_INIT_SYSV
    $(INSTALL) -D -m 0755 $(TPM2_ABRMD_PKGDIR)/S80tpm2-abrmd \
        $(TARGET_DIR)/etc/init.d/S38tpm2-abrmd
endef

Yocto

TODO: Document custom layer

Tips from kc8apf