Document mka/mkimg.sh/wrimg.sh build and flash workflow

README.md

@@ -7,6 +7,7 @@ Local manifest for building [LineageOS 23.2](https://lineageos.org/) (Android TV
 - A Linux build host with [LineageOS build dependencies](https://wiki.lineageos.org/requirements) installed
 - ~250GB free disk space
 - `repo` tool installed
+- An SD card (or other block device) at least 20GB, plus `sfdisk`/`kpartx`/`mkfs.vfat`/`mkfs.ext4` (all standard `util-linux`/`e2fsprogs` tools) for creating the flashable image
 
 ## Setup
 
@@ -38,9 +39,46 @@ source build/envsetup.sh
 breakfast tart
 
 # Build
-mka bacon
+mka
 ```
 
+Use plain `mka` (no target — this builds the default `droid` goal), **not** `mka bacon`. This device has no Android recovery (`TARGET_NO_RECOVERY := true`, U-Boot/extlinux boots it directly), which means `INTERNAL_OTA_PACKAGE_TARGET` is never assigned by the build system. `bacon`'s OTA-zip packaging rule depends on that variable and has no other build dependencies, so it fails almost instantly and aborts the whole build before `system.img`/`vendor.img` are even produced. Plain `mka` builds everything this device actually needs — `boot.img`, `system.img`, `vendor.img`, `ramdisk.img` — without ever touching that broken rule.
+
+## Creating a flashable image
+
+Once the build finishes, `device/rockchip/tart/mkimg.sh` assembles a bootable GPT image (U-Boot + FAT32 boot partition with `extlinux.conf`/kernel/DTB/ramdisk + system/vendor/metadata/userdata partitions):
+
+```bash
+# Run in the same shell you built in (needs TARGET_PRODUCT / ANDROID_PRODUCT_OUT
+# from `breakfast`), from the root of the source tree. Do NOT prefix with sudo —
+# root wouldn't see those env vars; the script escalates privileges internally
+# per-command only where needed:
+device/rockchip/tart/mkimg.sh
+```
+
+This produces `out/target/product/tart/lineage-<LINEAGE_VERSION>.img`. Write it to an SD card:
+
+```bash
+sudo dd if=out/target/product/tart/lineage-*.img of=/dev/sdX bs=4M status=progress
+```
+
+(Replace `/dev/sdX` with your SD card's device node — **not** a partition like `/dev/sdX1`.)
+
+### Fast re-flashing during development
+
+`device/rockchip/tart/wrimg.sh` writes individual partition images directly to an already-flashed physical device, without rebuilding the whole GPT image — useful when iterating on `system`/`vendor` without wanting to recreate the boot partition each time:
+
+```bash
+device/rockchip/tart/wrimg.sh            # writes boot + system + vendor
+device/rockchip/tart/wrimg.sh system     # writes system only
+device/rockchip/tart/wrimg.sh vendor     # writes vendor only
+device/rockchip/tart/wrimg.sh boot       # writes boot only
+device/rockchip/tart/wrimg.sh wipe       # reformats userdata
+device/rockchip/tart/wrimg.sh wipe-metadata  # reformats metadata
+```
+
+It auto-detects the target device by matching partition labels/sizes against `mkimg.sh`'s layout (`boot`/`system`/`vendor`/`metadata`/`userdata`), so the device must already have been flashed with an image from `mkimg.sh` at least once.
+
 ## Repositories
 
 This local manifest pulls in the following repositories from `git.bscubed.dev/lineage-rockchip/`: