Project glossary

mica

The Googlebook’s Android device codename (ro.product.device, read over adb 2026-10-20).

bluey

The ChromeOS reference baseboard for Qualcomm X1 devices in coreboot (src/mainboard/google/bluey); mica is one of its variants. Firmware branch firmware-bluey-16702.B.

Hamoa

Qualcomm’s platform name for the X1E80100 family; mainline Linux renamed x1e80100 device-tree files to hamoa.

Tributo

Codename of the Dell XPS 13 9345, the Windows sibling whose mainline device tree (x1e80100-dell-xps13-9345.dts, compatible dell,xps13-9345) is the starting point for this one.

Stock DT

The device tree Googlebook OS boots with: an LZ4-compressed vendor base DTB plus board and keyboard overlays in the dtbo_a partition (dtb_a is empty). It is used only as a hardware map (ADR 0004).

Recovery image

Google’s public mica-user/16471258/recovery.zip: one 19 GB GPT disk image. Build 16471258 is older than the installed 16560795.

Stock OS

Googlebook OS (codename Aluminium): Android 17 with a desktop shell, as shipped. Phase 1 reads it without changing it.

Stock drive and spare drive

The stock drive is the M.2 2230 SSD the laptop shipped with; it stays untouched in a drawer during experiments. The spare drive is a second 2230 SSD that takes every experiment (ADR 0002).

Gate

The condition that ends a phase. Work from the next phase does not start until its gate passes. Gate 1 = a proven way back to stock. Gate 2 = a mainline kernel’s own Linux version line, captured from the AP console, the panel or the ramoops readback.

Milestone

A named rung between the gates, M0 to M7 (ADR 0010), each with a “done when” bar. M0 and M1 coincide with Gates 1 and 2, M4 with Gate 3 and M6 with Gate 4. M5 (upstream-ready) ends the upstream hold. Per-feature state lives in docs/status.md.

Attempt

One boot of one image, with an ID YYYY-MM-DD-N and a row in the gitignored dumps/firstboot/attempts.tsv (scripts/attempt.sh). Repeat boots of the same image are added to its row.

Base image and test image

A base image is packaged with no debug command-line or DT extras. A test image has some (for example gbook.suspend=1). scripts/attempt.sh stick names which one the stick holds. Only a base image can become a release.

Release and version

A release is a base image with 3 clean cold boots by scripts/attempt.sh tally, which the owner would hand on. Its version is a CalVer annotated tag vYYYY.0M.0D[.MICRO] on the commit that built it (ADR 0011). A version names an image, and an attempt names one boot of it. uname -r carries the gbook commit it was built from, for example -gbook-g6934235 (+ for a tree with changes). A released image keeps that form, and its tag message maps the hash to the version.

Patch status

The first line of a kernel/patches/ file: Status: LOCAL, FROMLIST, FROMGIT or UPSTREAM, plus a reference (ChromiumOS’s words, with LOCAL for its CHROMIUM; ADR 0007 update). Patch numbers are never reused.

Recovery media

A USB drive (32 GB+) written by Google’s Device Recovery Utility Chrome extension; it reinstalls stock OS from the firmware recovery screen (Esc + F2, then Power, per Google’s Googlebook article; Esc + Refresh is the Chromebook combo).

Developer mode

ChromeOS firmware state that allows booting non-Google-signed kernels. On mica the recovery screen calls it “Unlock bootloader” / “Bootloader is unlocked”; it needs OEM unlocking turned on in Android first.

Kernel partition and FIT

A GPT partition of the ChromeOS-kernel type holding a vboot-signed image. On Arm the payload is a FIT (Flattened Image Tree): kernel plus one or more device trees, picked by compatible (google,mica-rev*-sku*).

ALink

Google’s USB bridge cable or dongle that depthcharge’s fastboot looks for as USB host; a Prolific PL27A1 also works. Without one, firmware fastboot runs over TCP via a USB-Ethernet adapter.

ABL

Qualcomm’s Android Bootloader, which loads Android boot images and speaks fastboot. mica does not use it (it boots through depthcharge, found 2026-10-21); kept here because the older plan assumed it.

RAM boot

fastboot boot <image>: boots an image once from memory without writing it to storage. mica’s depthcharge fastboot does not implement it; booting from a USB drive replaces it.

GSC

Google Security Chip on the board in place of a Windows TPM; on mica it is a Ti50 (coreboot TPM_GOOGLE_TI50). On Chromebooks it provides CCD.

CCD

Closed Case Debugging: UART consoles for the main processor and the EC over USB-C through the GSC, without opening the case. mica has it: CCD is Locked, with AP and EC console reads allowed Always (gsctool -a -I, 2026-10-21).

SuzyQ

The USB-C debug cable (here the Fyra Labs SuzyQ Board) that exposes CCD consoles to a second computer. On mica it works in the left port. the build host sees Ti50 18d1:5066, with ttys for the GSC shell, AP (uart21), EC and FPMCU.

EC

Embedded controller: battery, fans, keyboard, lid, Glowbar, LEDs. On mica it is a ChromeOS EC (Zephyr, Nuvoton NPCX9) over SPI, so mainline cros_ec drivers are the starting point; its mica overlay is partly private.

DTS and DTB

Device tree source and its compiled blob: the hardware description the kernel boots with on Arm.

GSI and DSU

Generic System Image, an AOSP system image for any Treble device; Dynamic System Updates boots one from new partitions without touching stock. The cheapest test after unlocking.

ROOT

The kernel stick’s partition 2, GPT name gbook-root, 8 GiB from sector 524288, declared by every KERN-A image’s GPT (ADR 0012, decision 3). The owner writes rootfs.ext4 to it; /init finds it as partition 2 of the disk that holds the kern_guid partition.

M3 rootfs

The Debian sid arm64 root filesystem of milestone M3, built by scripts/build-rootfs.sh from rootfs/packages.txt with mmdebstrap in the pinned container; rootfs/customize.sh adds its units. gbook-m3 is its capture service (GBOOK: m3-<key>= lines, a second netlog transfer); gbook-cage runs Ghostty under cage as user gbook.

mica (ssh host)

the build host’s ssh mica entry: the booted M3 rootfs at the Wi-Fi lease, key-only, user gbook with sudo (ADR 0012 update 2026-11-04). Reads are free; writes need the owner; one connection attempt per boot.