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Addon Development: Bass Lineout

This page is for Bass: Lineout (vendor/ax86-lite, tools/build.sh).

If you are on classic Bass OS with private/addons/ and unfold_bliss.sh, use the separate guide instead:

→ Addon Development: Legacy Bass OS

Do not mix the two. Lineout does not scan private/addons/ the way older Bass unfold did. Legacy Bass does not use vendor/ax86-lite/vendor_packages/ the same way.

Lineout overview

On Lineout, "addon" work falls into two buckets that both belong to this product line:

Bucket Where it lives How you enable it
Build packages vendor/ax86-lite/vendor_packages/ build.sh flags (--extras, --btnmgr, …)
Runtime overrides /data/misc/, GRUB flags, addon_init Push files + cmdline / setprop

Both are documented below. Neither is the old private/addons/ patchset model.

Build packages

Features ship as product packages in the vendor tree.

vendor/ax86-lite/vendor_packages/<Name>/
  Android.bp / *.mk
  README.md          # picked up by Ax86Docs when present
  init .rc / .sh     # optional; keep package-local when possible

Enable them from vendor/ax86-lite/tools/build.sh (see Building Bass OS):

Flag Packages / behavior
--extras Touch Mapper, Display Mapper, Config Overrides, Tweaks, Ax86Docs
--btnmgr Button Manager
--logger / --logging-enabled Ax86 Logger
--bootsight BootSight (+ ro.bass.fleet_mgmt=bootsight)
--smartdock SmartDock DFC
--ethernetconfig Ethernet Config

Adding a new Lineout package

  1. Create vendor_packages/YourFeature/ with a product .mk and (for apps) Android.bp.
  2. Wire it in ax86_lite.mk behind a flag (or always-on if that is intentional).
  3. Add the flag to tools/build.sh help and export defaults.
  4. Drop a README.md in the package so Ax86Docs picks it up on the next --extras build.
  5. Prefer package-local init.rc / scripts. Avoid editing core addon_init.rc unless the feature is shared early-boot plumbing.

App docs on this site:

Newer Lineout branches (addons/<id>/)

Some newer ax86-lite branches move packages under addons/<id>/ with addon.cfg and a compat symlink from vendor_packages/<Pkg>. See vendor_packages/Ax86ButtonManager/docs/PORTING-23.2.md in the vendor tree.

On current Lineage 21 / A14 Lineout trees, packages still live directly under vendor_packages/ and are gated by ax86_lite.mk + tools/build.sh. Use that layout unless your branch already has the addons/ integrator.

Runtime overrides (addon_init)

Lineout also supports on-device overrides without rebuilding the ISO. Scripts under /vendor/bin/addon_*.sh run from addon_init.rc after /data is available. They can bind-mount files from /data/misc/ over vendor/system paths, apply settings, and react to property triggers.

This is still the Lineout product path (same vendor tree). It is not the legacy Bass private-addon unfold flow.

Path Role
/vendor/etc/init/addon_init.rc Triggers early and late init, mapper props
/vendor/bin/addon_init.sh Orchestrator (DMI props, bind mounts, late boot)
addon_hardware.sh / addon_peripherals.sh / addon_packages.sh / addon_mappers.sh Helpers used by addon_init
/data/misc/ Fleet- or tech-provided override files

GRUB / cmdline toggles (Lineout)

Flag Effect
ADDON_IDC=1 Custom .idc files from /data/system/devices/idc
BLISS_INPUT_PORTS_ADDON=1 /data/misc/input-port-addon.xml for input↔display ports
ADDON_BOOTANIMATION=1 /data/misc/bootanimation.zip
ADDON_BASSINIT=1 Custom vendor init under /data/vendor/etc/init/

How-tos:

On --extras builds, Touch Mapper can generate the input-port file from Settings. Prefer that UI when available; GRUB flags still matter for headless imaging.

Config files and property triggers (Lineout)

Mechanism Docs
settings_*.conf, runtime_props.conf, device_config.conf Config Overrides
custom_device.prop (early ro.*) Same page; applied by addon_init before framework
Master apply setprop persist.ax86.update_configs 1
Per-mapper apply sys.ax86.display.update, sys.ax86.touch.update, sys.ax86.radio.update, sys.ax86.location.update

Vendor reference (also in Ax86Docs): OVERRIDES.md and VENDOR_DEPLOYMENT.md in vendor/ax86-lite.

Good uses for runtime overrides

  • Field fixes (digitizer axes, DPI) without a new ISO
  • Fleet imaging: push /data/misc files, set GRUB flags, reboot
  • Config Override examples under vendor/ax86-lite/docs/examples/

Runtime overrides are not how you ship a new privileged app. New apps go under vendor_packages/ with a build flag.