documentation/docs/Developer-Guide_Build-Options.md

• KERNEL_ONLY (yes|no):
  • leave empty to display selection dialog each time
  • set to "yes" to compile only kernel, u-boot and other packages for installing on existing Armbian system
  • set to "no" to build complete OS image for writing to SD card
• KERNEL_CONFIGURE (yes|no):
  • set to "yes" to configure kernel (add or remove modules or features). Kernel configuration menu will be brought up before compilation
  • set to "no" to compile kernel without changing default or custom provided configuration
• CLEAN_LEVEL (comma-separated list): defines what should be cleaned. Default value is "make,debs" - clean sources and remove all packages. Changing this option can be useful when rebuilding images or building more than one image
  • "make" = execute make clean for selected kernel and u-boot sources,
  • "images" = delete output/images (complete OS images),
  • "debs" = delete packages in output/debs for current branch and device family,
  • "alldebs" = delete all packages in output/debs,
  • "cache" = delete output/cache (rootfs cache),
  • "sources" = delete sources (all downloaded sources),
  • "extras" = delete additional packages for current release in output/debs/extra
• KERNEL_KEEP_CONFIG (yes|no):
  • set to "yes" to use kernel config file from previous compilation for the same branch, device family and version
  • set to "no" to use default or user-provided config file
• BUILD_DESKTOP (yes|no):
  • set to "yes" to build image with minimal desktop environment
  • set to "no" to build image with console interface only
• EXTERNAL (yes|no):
  • set to "yes" to compile and install some extra applications and drivers (only for default kernel branch):
    • USB redirector
    • Realtek RT8192 wireless driver
    • Mediatek MT7601U wireless - driver
    • Sunxi display control
    • hostapd from sources
• EXTERNAL_NEW (no|prebuilt|compile):
  • set to "prebuilt" to install extra applications from repository
  • set to "compile" to compile extra applications in chroot
• CREATE_PATCHES (yes|no):
  • set to "yes" will prompt you right before the compilation starts to make changes to the source code. Separate for u-boot and kernel. It will also create a patch out of this. If you want that this patch is included in the normal run, you need to copy it to appropriate directory
  • set to "no" compilation will run uninterrupted
• FORCE_CHECKOUT (yes|no):
  • set to "yes" to force overwrite any changed or manually patched kernel, u-boot and other sources
  • set to "no" to keep all changes to sources
• BUILD_ALL (yes|no|demo): cycle through all available board and kernel configurations and make images for all combinations

Hidden options to minimize user input for build automation:

• BOARD (string): you can set name of board manually to skip dialog prompt
• BRANCH (default|next|dev): you can set kernel and u-boot branch manually to skip dialog prompt; some options may not be available for all devices
• RELEASE (wheezy|jessie|trusty|xenial): you can set OS release manually to skip dialog prompt; use this option with KERNEL_ONLY=yes to create board support package

Hidden options for advanced users (default values are marked bold):

• USE_CCACHE (yes|no): use a C compiler cache to speed up the build process
• PRIVATE_CCACHE (yes|no) use $DEST/ccache as ccache home directory
• PROGRESS_DISPLAY (none|plain|dialog): way to display output of verbose processes - compilation, packaging, debootstrap
• PROGRESS_LOG_TO_FILE (yes|no): duplicate output, affected by previous option, to log files output/debug/*.log
• USE_MAINLINE_GOOGLE_MIRROR (yes|no): use googlesource.com mirror for downloading mainline kernel sources, may be faster than git.kernel.org depending on your location
• FORCE_USE_RAMDISK (yes|no): overrides autodetect for using tmpfs in new debootstrap and image creation process
• FIXED_IMAGE_SIZE (integer): create image file of this size (in megabytes) instead of minimal
• COMPRESS_OUTPUTIMAGE (yes|no): create compressed archive with image file and GPG signature for redistribution
• SEVENZIP (yes|no): create .7z archive with extreme compression ratio instead of .zip
• ROOTFS_TYPE (ext4|f2fs|btrfs|nfs|fel): create image with different root filesystems instead of default ext4. Requires setting FIXED_IMAGE_SIZE to actual size of your SD card for F2FS and BTRFS