What this format boundary means
A safety-first mGBA RTC-Appended Save guide for identifying the intended representation, preserving an untouched source copy, and choosing only a verified compatible Tool. The format hub currently defines this boundary as: mGBA raw GBA battery saves with the verified optional 16-byte RTC record. RTC data is preserved or stripped only through explicit size-checked workflows.
Treat that description as a representation boundary rather than a shortcut to game-specific meaning. A recognizable filename, extension, or common byte length can help you locate a candidate file, but those surface clues do not prove that the file belongs to the expected schema. The compatible Tool must still validate the internal structure that its support notes require.
Make a complete backup before inspection
Close the game, emulator, launcher, or synchronization client before copying the live save. Keep one untouched backup outside the active save directory and label it so you can distinguish it from later working copies. Preserve the complete representation expected by the workflow; do not strip headers, wrappers, sidecars, metadata blocks, or companion files simply because the payload looks familiar.
For container or wrapper formats, back up the wrapper as well as any extracted payload you later create. For raw-card or filesystem images, copy the whole image rather than only a directory entry or visible save slot unless a verified extraction Tool explicitly documents a narrower boundary. This keeps rollback possible if identification later proves wrong.
Choose a verified compatible Tool
Verified Tool context for this format currently includes: mGBA Save Converter. These relationships show existing supported surfaces in the SaveEditor catalog; they are not a promise that every file sharing the format name, extension, or size will pass every listed Tool.
Prefer a read-only inspector, fingerprint, or validator first when one exists. If a Tool performs extraction, conversion, migration, repair, or editing, read its individual authority statement before continuing. A format-level Guide cannot widen that Tool authority, cannot turn a candidate-only file into a verified representation, and cannot make unsupported game fields safe to edit.
Verify the working copy and preserve rollback
Record the original file size and a cryptographic hash such as SHA-256 when practical. After any authorized transformation, keep the output separate from the source and reopen it through the same strict parser or validator used by the Tool. If the workflow documents an exact byte-scope or payload-equality requirement, verify that condition before replacing anything in the live save location.
Keep the untouched backup until the target game, emulator, or utility has loaded the result successfully and you have confirmed the expected profile or slot. If the parser refuses the file, if the output cannot reopen, or if the format boundary is uncertain, stop and return to the original copy instead of forcing the file through a loosely related workflow.