Jetson Derive Carrier

jetson-derive-carrier

Customize first-run gate for any customize-* skill on a custom

carrier. Resolve the active target per

target-platform-contract.md.

Refuse if no custom_carrier: block, or if

<source.root_path>/Linux_for_Tegra/.git is missing

(jetson-init-source first). Template file create/copy rows land in a

single overlay-tracker commit and copy directly to the

custom-carrier-renamed target path — reference-named pristine files

are never staged (see Fork plan for the local rule, which

overrides the standard pristine + customization split from the

workflow);

conf-chain discovery follows

per-board conf dispatch.

Kernel base DTB is not forked — carrier deltas layer as a DT

overlay wired via OVERLAY_DTB_FILE.

Identifiers (from active profile): <chip> from

reference_devkit.module.id via

catalogue (unknown →

warn, fallback tegra234); <module-id>/<module-sku> from

reference_devkit.module; <carrier-id>/<carrier-sku> from

reference_devkit.carrier; <custom-id>/<custom-sku>/

<custom-flash-conf> from custom_carrier. <real-conf> =

readlink <bsp_image.root_path>/Linux_for_Tegra/<reference_devkit.flash_config>

(NVIDIA convention <devkit>.conf → <carrier>-<module>-a<rev>.conf;

warn + treat top-level as real + skip symlink-wrapper row if not a

symlink).

<custom-id> is a custom carrier board token, not necessarily an

NVIDIA-style pNNNN ID. Use it verbatim in dash-form filenames and DT

compatible strings. When a target file family uses p-stripped numeric

tokens, derive <custom-id-file-token> as NNNN only if <custom-id>

matches ^p[0-9]{4}$; otherwise use <custom-id> unchanged. Do not

reject custom carrier IDs merely because they do not start with p.

Instructions

The fork plan below is the instruction set: one discovery pass, then a

row-by-row fork of the per-board fileset, gated by the commit-message

preview before each git commit.

Fork plan

Every git commit produced by this skill — in the overlay tracker

(Linux_for_Tegra/) or the hardware/ source repo — runs through

the

commit message preview gate.

Surface the staged file list + proposed message to the operator

and require accept / edit / cancel before each git commit; on

cancel leave the index staged for manual resolution.

Materialize renamed forks even when bytes do not change. For every

accepted fork-plan row, create and track the custom-carrier target path;

do not skip a missing target because the fork is only a rename/copy or is

byte-identical to the reference. This includes BCT forks such as pinmux,

GPIO/GPIOINT, padvoltage/PMC, misc, and MB2 misc. Skip only when the

Acceptance column allows it, the source is an explicit warn-and-skip

miss, or the expected target path is already tracked; in the last case,

report it as already derived and do not create an empty commit.

**Template file create/copy rows squash into one overlay-tracker

commit, and reference-named pristine files are never staged.** All

rows that materialize a new (template-derived) file in the overlay

tracker — board flash-conf, flash-conf symlink, MB1 BCT (pinmux,

GPIO/GPIOINT, padvoltage/PMC, misc), MB2 BCT (misc), BPMP DTB (when

opted in), nvpmodel, nvfancontrol — copy directly from

<bsp_image.root_path>/Linux_for_Tegra/<rel>/<reference-name> to

<source.root_path>/Linux_for_Tegra/<rel>/<custom-name> with any

content edits applied before staging. The reference-named

(<carrier-id>-<carrier-sku>-keyed) filename is never staged or

committed in the overlay tracker — only the custom-carrier-renamed

file is tracked. This overrides the standard pristine + customization

split from

commit batching.

All such rows land in a single overlay-tracker commit that adds:

(i) the custom-carrier-named files at their target paths with content

already applied, (ii) the flash-conf symlink, and (iii) the targeted

flash-conf content rewrites inside the renamed flash-conf for

PINMUX_CONFIG / GPIO_CONFIG / GPIOINT_CONFIG / PMC_CONFIG /

MISC_CONFIG / MB2_BCT (plus BPFDTB_FILE when BPMP DTB is opted

in). Rows that edit existing upstream files instead of creating

templates — the nvpower.sh patch — and the overlay wire-up

(OVERLAY_DTB_FILE+= append to the just-created flash-conf fork,

treated as a temporally distinct phase per

commit batching)

remain separate commits per their own rows. The DT overlay skeleton

commits in bsp_sources/hardware/, not the overlay tracker, so it is

unaffected. The commit message preview gate fires once on the

squashed commit; warn-and-skipped rows do not contribute, and if every

row in the bundle is already tracked the commit is omitted entirely.

Discovery (single batched pass)

Run one discovery pass; do not interleave with staging. **Do not

truncate listings** — every candidate filename in each scanned

directory must be visible to the matcher. head, tail, | head -N,

| tail -N, and any other row-limiting filter are out of bounds for

this step; use ls -1 / find unclipped, or grep on the full output.

Truncating risks false warn-and-skip calls when the matching file

sits past the cutoff. Capture:

• Flash-conf vars: DTB_FILE / TBCDTB_FILE / BPFDTB_FILE /

PINMUX_CONFIG / PMC_CONFIG / GPIO_CONFIG / GPIOINT_CONFIG.

DTB_FILE / TBCDTB_FILE are captured for reference only so

the overlay wire-up can derive <dtb-stem> for the overlay

filename — they are never rewritten by this skill.

• BCT .dts at bootloader/generic/BCT/; .dtsi siblings live

one level up at bootloader/ — NOT alongside.

• nvpmodel: nvpmodel_<module-id>_<module-sku>*.conf. nvfancontrol:

nvfancontrol_<module-id>_<module-sku>_<carrier-id>_<carrier-sku>.conf.

• nvpower.sh anchors for (a)–(d): <carrier-id> cvb branch,

<module-id>-<module-sku> SKU elif, tegra<chip> nvpmodel

cascade, tegra<chip> nvfancontrol cascade.

| File / category | Discovery | Acceptance | Fork rule |

|---|---|---|---|

| Board flash conf | <real-conf> | Always | Filename sub <carrier-id>-<carrier-sku> → <custom-id>-<custom-sku>. Content sub is targeted, not blanket: rewrite RHS only for vars whose file this skill forks — PINMUX_CONFIG, PMC_CONFIG, GPIO_CONFIG / GPIOINT_CONFIG, MISC_CONFIG, MB2_BCT. Other carrier-keyed vars (DTB_FILE, TBCDTB_FILE, SCR_CONFIG, PMIC_CONFIG, DEVICEPROD_CONFIG, PROD_CONFIG, MINRATCHET_CONFIG, UPHY_CONFIG, dynamic OVERLAY_DTB_FILE+=) MUST stay at reference values — their files aren't forked here and a blanket sed would point them at nonexistent files. DTB_FILE / TBCDTB_FILE specifically: base DTB is not forked; the overlay row appends a new OVERLAY_DTB_FILE+= line instead. BPFDTB_FILE: opt-in extra commit. Never touch <chip>, <module-id>, xxxx. |

| Flash-conf symlink | Unconditional | Always (skip if <real-conf> not a symlink) | New symlink <custom-flash-conf> → flash-conf fork |

| MB1 BCT pinmux | PINMUX_CONFIG + #include follow ¶ | Always | Rename rule † |

| MB1 BCT GPIO | GPIO_CONFIG/GPIOINT_CONFIG + #include follow ¶ | Always | Rename rule † |

| MB1 BCT padvoltage | PMC_CONFIG + #include follow ¶ | Always | Rename rule † |

| MB1 BCT misc | MISC_CONFIG + #include follow ¶ | Always | Rename rule † |

| MB2 BCT misc | MB2_BCT + #include follow ¶ | Always | Rename rule † |

| Kernel DTB + source DTS | (reference only — see header) | Never forked | Base DTB stays at reference. No pristine binary copy in the overlay tracker; no source DTS fork in bsp_sources/hardware/. Carrier deltas live entirely in the DT overlay (next row). |

| DT overlay skeleton (NEW) | Unconditional | Always | Create <source.root_path>/hardware/nvidia/<chip>/nv-public/overlay/<chip>-<custom-id>-<custom-sku>+<module-id>-<module-sku>.dts (skeleton ‡); commit in hardware/, push to origin |

| Per-dir Makefile registration | <source.root_path>/bsp_sources/hardware/nvidia/<chip>/nv-public/overlay/Makefile | Always | Append dtbo-y += <chip>-<custom-id>-<custom-sku>+<module-id>-<module-sku>.dtbo after the last literal-named dtbo-y += entry (BEFORE the $(addprefix $(makefile-path)/,$(dtbo-y)) prefix block — inserting after dtbo-y += $(old-dtbo) silently drops the .dtbo). Same position-sensitive idiom and snippet as the composite slot's Makefile patch in ../jetson-build-source/references/composite-registration.md#makefile-patch-idempotent-position-sensitive. Commit in hardware/. Without this row, nvidia-dtbs never produces the .dtbo referenced by the next row's OVERLAY_DTB_FILE+= line and flash.sh aborts mid-flash on the missing file. |

| Overlay wire-up | Unconditional | Always | Append OVERLAY_DTB_FILE+=",<chip>-<custom-id>-<custom-sku>+<module-id>-<module-sku>.dtbo" to flash-conf fork (extra commit) |

| nvpmodel config | rootfs/etc/nvpmodel/nvpmodel_<module-id-num>_<module-sku>.conf | Always | Filename: append _<custom-id-file-token>_<custom-sku> |

| nvfancontrol config | rootfs/etc/nvpower/nvfancontrol/nvfancontrol_<module-id-num>_<module-sku>_<carrier-id-num>_<carrier-sku>.conf | Always | Filename: substitute carrier portion (append _<custom-id-file-token>_<custom-sku> if source is module-keyed only) |

| nvpower.sh patch | rootfs/etc/systemd/nvpower.sh | Always | Pristine + single customization commit with 4 insertions: (a) cvb cascade elif [[ "${machine}" =~ "<custom-id>" ]]; then cvb="<custom-id-file-token>" before reference; (b) inside module-SKU branch set machine="<module-id>-<module-sku>-<custom-id>-<custom-sku>"; (c) nvpmodel cascade branch for composite machine key → conf_file= nvpmodel fork; (d) cvb-keyed nvfancontrol cascade branch → conf_file= nvfancontrol fork |

| BPMP DTB | prebuilt at bootloader/generic/<BPFDTB_FILE> (alt naming: no p prefix, xxxx SKU) | Opt-in y/N, default N — module-level, usually shared with reference | Fork binary: pristine + filename sub -<carrier-id-num>- → -<custom-id-file-token>- (content unchanged). Extra commit on flash-conf fork rewriting BPFDTB_FILE to the renamed binary. |

¶ #include follow. Scan each captured .dts for `#include

"..."` directives anywhere in the file (NVIDIA BSPs put them

inside BCT node bodies); carrier-keyed includes join the fork list.

Stop at one level.

† Rename rule. Carrier-keyed source (e.g.

…-p3834-xxxx-p4071-0000.dts) → filename sub

<carrier-id>-<carrier-sku> → <custom-id>-<custom-sku>; rewrite the

flash-conf variable (e.g. PINMUX_CONFIG) to the renamed filename in

the same customization commit. **Module portion is preserved

verbatim from pristine** — if pristine has p3834-xxxx, fork keeps

p3834-xxxx; if pristine has p3834-0008, fork keeps p3834-0008.

Never pin module-SKU on your own. Same rule for any other xxxx

wildcard in the carrier-SKU position when pristine uses it (e.g.

p4071-xxxx → p1234-xxxx). Module-keyed

source (e.g. …-p3767-dp-a03.dtsi) → append

_<custom-id-file-token>_<custom-sku> (underscore-form) or

-<custom-id>-<custom-sku> (dash-form) plus an extra commit on

flash-conf fork rewriting the variable (e.g. PINMUX_CONFIG) to the

suffixed name. Content never substituted by default; prompt if

content holds a literal carrier-id-sku self-reference.

‡ Overlay skeleton. DT plugin overlay (/plugin/;) with one

fragment@0 at target-path = "/"; inside __overlay__ set

model = "<custom_carrier.name> carrier board" and `compatible =

"nvidia,<custom-id>-<custom-sku>+<module-id>-<module-sku>",

"nvidia,<chip>". nvpower.sh machine narrowing reads compatible`.

Edit verification

Re-grep after every sed / patch. sed silently no-ops on miss;

exit code 0 proves nothing. Multi-line replacements: use Python

str.replace(old, new), not multi-line sed (brittle to whitespace

drift, silent no-ops). Refuse to commit on verification miss.

Summary. Print forks per repo (count + commit SHAs), BPMP-DTB

decision, warn-and-skipped rows (mandatory source file missing on

this BSP — don't fail the run), overlay path written.

Examples

Trigger phrases the operator might use:

derive custom carrier
bootstrap custom carrier
fork carrier board from reference devkit

Minimal custom_carrier: block in the active profile that the skill

expects to find:

custom_carrier:
  id: p1234            # any token; need not be NVIDIA pNNNN style
  sku: 0000
  flash_config: p1234.conf
  name: Acme Custom Carrier

Purpose

Customize the per-board fileset for a new carrier board so downstream

customize-* skills, nvpower.sh, and the boot chain land on the

custom carrier instead of the reference devkit. Base DTB stays at the

reference; carrier deltas live in a DT overlay so a re-derive against

a new reference BSP only needs to re-run this skill.

Prerequisites

• Active profile resolved per

target-platform-contract.md

with a custom_carrier: block (id, sku, flash-conf, friendly name).

• source.root_path/Linux_for_Tegra/.git initialized — run

/jetson-init-source first; this skill refuses if the overlay

tracker is missing.

• bsp_image.root_path populated by /jetson-init-image so the

reference flash-conf symlink can be resolved.

• reference_devkit: populated (module + carrier) so the rename rule

has carrier-id/sku tokens to substitute away from.

Limitations

• Kernel base DTB and its source DTS are not forked — carrier

deltas must layer through the DT overlay wired via

OVERLAY_DTB_FILE.

• BPMP DTB fork is opt-in (default OFF). Most carrier swaps share the

reference BPMP DTB; only opt in when board power/clock topology

diverges.

• Flash-conf content substitution is targeted, not blanket. Vars

whose files this skill does not fork (DTB_FILE, TBCDTB_FILE,

SCR_CONFIG, PMIC_CONFIG, DEVICEPROD_CONFIG, PROD_CONFIG,

MINRATCHET_CONFIG, UPHY_CONFIG, dynamic OVERLAY_DTB_FILE+=)

stay at reference values — rewriting them would point at files that

do not exist.

• Custom-carrier IDs need not follow NVIDIA pNNNN style; the

p-stripped numeric token is derived only when the ID matches

^p[0-9]{4}$.

• Does not customize module-level files. Use the relevant

jetson-customize-* skill for pinmux, clocks, fan curves,

nvpmodel, PCIe, UPHY, USB, MGBE, or camera deltas.

Troubleshooting

• Refuses with "no custom_carrier: block" — declare the block in

the active profile before re-running; the skill will not infer it.

• Refuses with ".git missing in Linux_for_Tegra/" — overlay

tracker not initialized. Run /jetson-init-source first.

• "<real-conf> not a symlink" — NVIDIA convention is a

<devkit>.conf symlink to <carrier>-<module>-a<rev>.conf; if the

top-level is the real conf, the skill warns, treats it as real, and

skips the symlink-wrapper row. Not an error.

• sed reported success but the edit is missing — sed silently

no-ops on miss. The skill re-greps after every patch and refuses to

commit on verification miss; for multi-line replacements switch to

Python str.replace.

• "chip: unknown" / fallback to tegra234 — module ID is not in

the catalogue; update

the catalogue rather than override in the profile.

• Commit message preview prompt blocks the run — expected gate per

commit-batching;

accept, edit, or cancel. On cancel the index is left staged for

manual resolution.

• A mandatory source file is missing on this BSP — the row is

recorded as warn-and-skipped in the summary; the rest of the run

still completes.