====== Filesystem & partitions ======

How the head unit lays out its storage — worth understanding before you change anything, and the
basis for a safe backup. The eMMC is ''mmcblk0'' (~29 GB). Because ''adbd'' runs as **root**, the raw
partitions are readable, so a byte-exact image of the whole device is possible.

===== Partition layout (''mmcblk0'', ~29 GB) =====

^ Partition ^ Size ^ Mount ^
| p1, p2, boot0/1 | 8 MB | bootloader / boot images |
| p4 | 5.3 GB (528 MB used) | ''/data'' |
| p5 | 512 MB | ''/system'' |
| p6 | 512 MB | ''/cache'' |
| p7 | 8 MB | ''/device'' (ro config) |
| p9 | 1 GB | ''/vendor'' |
| p10–p13 | 256 MB / 1 MB… | vendor / firmware |
| p14 | 21.5 GB (339 MB used) | internal_sd (vfat) |

===== Making a full backup =====

**Do this before modifying anything.** With root ''adbd'' a complete image is straightforward:
md5-verified partition images plus a file-level copy of ''/system'' and ''/vendor''.

**Gotcha — the old ADB:** a normal shell corrupts binary data (the PTY translates line endings) and
''exec-out'' is unsupported on this old adbd, so stream binary through **base64 + gzip** (7-bit,
PTY-safe). ''adb pull'' itself //is// binary-safe (it uses the sync protocol).