# Build options

These parameters are meant to be applied to the `./compile.sh` command. They are **all** optional.  They can also be added to your [build configuration file](/Developer-Guide_Build-Preparation/#providing-build-configuration) to save time. Default values are marked **bold** if applicable. 

## Main options


- **KERNEL_ONLY** ( yes | no ):
    - yes: compiles only kernel, U-Boot and other packages for installation on existing Armbian system
    - no: build complete OS image for writing to SD card
    - leave empty to display selection dialog each time
- **KERNEL_CONFIGURE** ( yes | no ):
    - yes: Automatically call kernel's `make menuconfig` (add or remove modules or features)
    - no: Use provided kernel configuration provided by Armbian
    - leave empty to display selection dialog each time
- **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 `cache/rootfs` (rootfs cache)
    - oldcache: remove old `cache/rootfs` except for the newest eight files
    - sources: delete `cache/sources` (all downloaded sources)
    - extras: delete additional packages for current release in `output/debs/extra`
- **REPOSITORY_INSTALL** (comma-separated list): list of core packages which will be installed from repository
    - Available options: `u-boot`, `kernel`, `bsp`, `armbian-bsp-cli`,`armbian-bsp-desktop`,`armbian-desktop`,`armbian-config`, `armbian-firmware`
    - Set to "" to use packages one from local output or build if not available
- **KERNEL\_KEEP\_CONFIG** ( yes | no ):
    - yes: use kernel config file from previous compilation for the same branch, device family and version
    - no: use default or user-provided config file  
- **BUILD_MINIMAL** ( yes | no ):
    - yes: build bare CLI image suitable for application deployment. This option is **not compatible** with `BUILD_DESKTOP="yes"` and `BUILD_EXTERNAL="yes"`
    - no: default CLI package selection
- **BUILD_DESKTOP** ( yes | no ):
    - yes: build image with minimal desktop environment
    - no: build image with console interface only  
- **EXTERNAL** ( yes | no ):
    - yes: compile and install extra applications and firmware  
- **BSPFREEZE** ( yes | no ): 
    - yes: freeze (from update) armbian packages when building images (U-Boot, kernel, DTB)  
- **INSTALL_HEADERS** ( **no** | yes ):
    - yes: install kernel headers  
- **EXTERNAL_NEW** ( no | prebuilt | compile ):
    - prebuilt: install extra applications from repository
    - compile: compile extra applications in chroot  
- **CREATE_PATCHES** ( yes | **no** ):
    - yes: prompt right before the compilation starts to make changes to the source code for both U-Boot and kernel. From these changes patch files will be created and placed in `output` directory. If you want these patches included in a normal run (without CREATE_PATCHES to say) these files need to be copied to the appropriate directories. Also see [user provided patches](https://docs.armbian.com/Developer-Guide_User-Configurations/#user-provided-patches).
- **BUILD_ALL** ( yes | no | demo ): cycle through all available board and kernel configurations and make images for all combinations  
- **LIB_TAG** ( master | "branchname" ):
    - set to `master` to compile from the master branch (default)
    - set to another "branchname" to compile from any other branch available. Check [here](https://github.com/armbian/build/branches) for available branches  
- **CARD_DEVICE** ( /dev/sdX ): set to the device of your SD card. The image will be burned and verified using Etcher for CLI.
- **CRYPTROOT_ENABLE** ( yes | no ): enable LUKS encrypted rootfs
    - `CRYPTROOT_PASSPHRASE="MYSECRECTPASS"` mandatory
    - `CRYPTROOT_SSH_UNLOCK=yes` Default: `yes`
    - `CRYPTROOT_SSH_UNLOCK_PORT=2222` Default: `2022`
    - `CRYPTROOT_PARAMETERS="custom cryptsetup options"` Default: `--pbkdf pbkdf2` (May not contain `=`; separate with spaces)
    - **Note:** This function might not work well with all distributions. Debian Buster and Stretch were tested. For building under Docker you have to use privileged mode which can be enable in `userpatches/config-docker`.
    - **Warning:** This feature was added as community contribution and mostly functional. Under some circumstances though the prompt will not be shown. Therefore it should be considered experimental. Check [here](https://github.com/armbian/build/commit/681e58b6689acda6a957e325f12e7b748faa8330) and [here](https://github.com/armbian/build/issues/1183)
    - **Hint:** If you want to do the encryption part from scratch check out [this](https://forum.armbian.com/topic/15618-full-root-filesystem%C2%A0encryption%C2%A0on-an-armbian-system-new-replaces-2017-tutorial-on-this-topic/) forum post.  
  
  
## Hidden options to minimize user input for build automation
- **BOARD** ( `string` ): set name of board manually to skip dialog prompt
- **BRANCH** ( `legacy` | `current` | `edge` ): set kernel and U-Boot branch manually to skip dialog prompt; some options may not be available for all devices
- **RELEASE** ( `stretch` | `buster` | `bullseye` | `bionic` | `focal` | `hirsute` ): set OS release manually to skip dialog prompt; use this option with `KERNEL_ONLY=yes` to create board support package  
- **ARMBIAN_CACHE_ROOTFS_PATH** ( `string` ): bind mount cache/rootfs to defined folder
- **ARMBIAN_CACHE_TOOLCHAIN_PATH** ( `string` ): bind mount cache/toolchain path to defined folder
  
## Hidden options for advanced users (default values are marked **bold**)
- **EXPERT** ( yes | **no** ): Show development features and boards regardless of its status in interactive mode
- **USERPATCHES_PATH** ( **userpatches/** ): set alternate path for location of `userpatches` folder
- **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
- **SKIP_EXTERNAL_TOOLCHAINS** ( yes | **no** ) don't download and use Linaro toolchains, by default placed in cache/toolchain (and configurable with **ARMBIAN_CACHE_TOOLCHAIN_PATH**)
- **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`
- **NO_APT_CACHER** ( **yes** | no ): disable usage of APT cache. Default `yes` in containers, but can be overridden
- **DISABLE_IPV6** ( **true** | false ): The distant future, the year Two-Thousand.  Set false to allow Aria2c to use a modern ip protocol.
- **NO_HOST_RELEASE_CHECK** ( yes | **no** ): overrides the check for a supported host system
- **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
- **USE_GITHUB_UBOOT_MIRROR** ( yes | **no** ): use unofficial Github mirror for downloading mainline U-Boot sources, may be faster than `git.denx.de` depending on your location
- **SYNC_CLOCK** ( **yes** | no ): sync system clock on builder before start image creation process
- **OFFLINE_WORK** ( yes | **no** ): skip downloading and updating sources as well as time and host check. Set to "yes" and you can collect packages without accessing the internet
- **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
- **BOOTSIZE** ( `integer` **96** ): set size (in megabytes) for separate /boot filesystem. Used if **ROOTFS_TYPE** set to non-ext4
- **COMPRESS_OUTPUTIMAGE** (comma-separated list): create compressed archive with image file and GPG signature for redistribution
    - sha: generate SHA256 hash for image
    - gpg: sign image using gpg
    - 7z: compress image, hash and signature to 7z archive
    - gz: compress image only using gz format
    - yes: compatibility shorcut for `sha,gpg,7z`
- **SEVENZIP** ( yes | **no** ): create .7z archive with extreme compression ratio instead of .zip
- **BUILD_KSRC** ( **yes** | no ): create kernel source packages while building...
- **INSTALL_KSRC** ( yes | **no** ): ... and pre-install these kernel sources on the image 
- **ROOTFS_TYPE** ( **ext4** | f2fs | btrfs | xfs | nfs | fel ): create image with different root filesystems instead of default `ext4`. Requires setting `FIXED_IMAGE_SIZE` to something smaller than the size of your SD card for `F2FS`
- **BTRFS_COMPRESSION** ( lzo | none | **zlib** | zstd ): when choosing `ROOTFS_TYPE=btrfs` select `btrfs` filesystem compression method and compression level. By default the compression is `zlib`.  
When selecting `zstd` or setting zlib compression level(`zlib:[1-9]`) user must ensure kernel version is **>=4.14.x**.  
When selecting zstd compression level (`zstd:[1-15]`) both the host and the target kernel version must be **>=5.1.x** since kernel started supporting zstd compression ratio only from 5.1 on.  
*Note:* The script does not check the legality of input variable (compression ratio). Input like `zlib:1234` is legal to the script but illegal to the kernel. Beware that setting this option does affect image creation only (shrinking disk size) and will not adjust `/etc/fstab` so it is up to the user to later edit `/etc/fstab` if compression in daily operation is also wanted (beware of serious performance penalties with random IO patterns and heavy compression algorithms!).
- **FORCE_BOOTSCRIPT_UPDATE** ( yes | no ): 
    - yes: force bootscript to get updated during bsp package upgrade
- **NAMESERVER** ( `IPv4 address` ): the DNS resolver used inside the build chroot. Does not affect the final image. Default: `1.0.0.1`
- **DOWNLOAD_MIRROR** ( `china` | `bfsu` ): select download mirror for `toolchain` and `debian/ubuntu packages`
	- `china`: use `mirrors.tuna.tsinghua.edu.cn`, it will be very fast thanks to Tsinghua University
	- `bfsu`: use `mirrors.bfsu.edu.cn`, mirror of Beijing Foreign Studies University  
	- leave empty to use official source
- **ARMBIAN_MIRROR** (auto): override automated mirror selection, example 'ARMBIAN_MIRROR="https://yourlocalmirror.com"'
- **MAINLINE_MIRROR** ( `google` | `tuna` | `bfsu` ): select mainline mirror of `linux-stable.git`
	- `google`: use mirror provided by Google, the same as `USE_MAINLINE_GOOGLE_MIRROR=yes`
	- `tuna`: use mirror provided by Tsinghua University
	- `bfsu`: use mirror provided by Beijing Foreign Studies University which is similar to `tuna`
	- leave empty to use offical `git.kernel.org`, may be very slow for mainland China users
- **UBOOT_MIRROR** （ `github` | `gitee` : select mainline mirror of `u-boot.git`
	- `github`: use mirror provided by github, the same as `USE_GITHUB_UBOOT_MIRROR=yes`
	- `gitee`: use mirror provided by Gitee, a Chinese git services
	- leave empty to use offical `source.denx.de`, may be very slow for mainland China users
- **GITHUB_MIRROR** ( `fastgit` | `gitclone` | `cnpmjs` ): select download mirror for GitHub hosted repository
	- `fastgit`: use mirror provided by fastgit.org
	- `gitclone`: use mirror provided by gitclone.com
	- `cnpmjs`: use mirror provided by cnpmjs.org
	- leave empty to connect directly to GitHub, may be very slow for mainland China users
- **REGIONAL_MIRROR** ( `china` ): select mirrors based on regional setting, will not overwrite explicitly specified mirror option
	- `china`: MAINLINE_MIRROR=`tuna`, UBOOT_MIRROR=`gitee`, GITHUB_MIRROR=`fastgit`, DOWNLOAD_MIRROR=`china`
	- leave empty to use default settings
- **USE_TORRENT** ( yes | **no** ): use torrent to download toolchains and rootfs
- **ROOT_FS_CREATE_ONLY** ( yes | **no** ): set to yes to force local cache creation
- **EXTRAWIFI** ( **yes** | no ): include several drivers for [WiFi adapters](https://github.com/armbian/build/blob/1914066729b7d0f4ae4463bba2491e3ec37fac84/lib/compilation-prepare.sh#L179-L507)
- **WIREGUARD** ( **yes** | no ): include Wireguard for kernels before it got upstreamed to mainline. Will lose functionality soon.
- **AUFS** ( **yes** | no ): Include support for [AUFS](https://en.wikipedia.org/wiki/Aufs)
- **SKIP_BOOTSPLASH** ( yes | **no** ): Use kernel bootsplash. Disable in case of troubles
