`openremap merge`

Combine two recipes built from the same family of originals into one — like git's three-way merge: the stock binary is the common ancestor, recipe A is "ours", recipe B is "theirs".

Use this to compose small, reusable mods (egr_off, stage1, dpf_off) into one recipe per car instead of keeping monolithic per-car recipes.

New here? Read the plain-English introduction first.

Usage

openremap merge <A.remap> <B.remap> [--stock original.bin] [-o merged.remap] [--strict]

Arguments

Argument	Required	Description
`A.remap`	Yes	First recipe (`.remap`, `.json`, or `.openremap`).
`B.remap`	Yes	Second recipe — same accepted extensions.

Options

Option	Default	Description
`--stock <path>`	required unless the recipes share `ecu.sha256`	The common stock binary. Every instruction from both recipes is validated against it.
`--output PATH`, `-o`	stdout	Write the merged recipe to this file.
`--strict`	off	Abort instead of skipping instructions that don't match the stock.
`--help`		Show help and exit.

Merge rules

Situation	Result
Same offset, same values	One copy kept
Same offset, different values	Conflict — same address, different edit; a human decides
Overlapping ranges, different boundaries	Conflict — edit boundaries disagree; a human decides
Different, non-overlapping offsets	Both kept

Why the stock is the merge base

Neither tuner needs the other's exact original file. Every instruction from both recipes is validated against your stock (original bytes at offset). A recipe built from a slightly different original (for example, the VIN area differs) fails only for the instructions that truly differ — those are reported and skipped (or abort the merge with --strict).

Without --stock, the merge requires both recipes to declare identical ecu.sha256 + match_key.

The merged recipe re-checks anchor uniqueness (Guard 3) against the stock and re-annotates the maps layer (schema 4.4) when --stock is given.

Example

# Both tuners worked from your stock.bin
openremap merge egr_off.remap stage1.remap --stock stock.bin -o both.remap

  ✅ Merged egr_off.remap (12 instructions) + stage1.remap (67 instructions) → 79 instructions.
  ⚠  egr_off.remap: 1 instruction(s) skipped — they do not match the stock binary
     (…). This recipe was likely built from a slightly different original.

  Saved merged recipe to both.remap (schema 4.4)

On a real conflict (same offset, different values), the merge stops with a clear error and exit code 1 — nothing is guessed, no partial merge is written.

Notes

merge reads the two recipe files and (optionally) the stock binary; it never modifies any of them.
Recipe files are JSON — open them in any editor to inspect the changes.
Exit codes: 0 on success, 1 on a conflict, an unreadable/malformed recipe, or --strict failure.

openremap merge