can1357/oh-my-pi · error · ArchiveError

Invalid CPIO archive: newc checksum field must be zero

Error message

Invalid CPIO archive: newc checksum field must be zero

What it means

For the 'new ASCII' magic '070701' (plain newc), the 13th header field is the checksum and must be 0; only the '070702' (CRC) variant carries a meaningful checksum. The library throws ArchiveError when a newc header declares magic 070701 but a non-zero checksum, an internally inconsistent header. It protects users from silently skipping verification or trusting contradictory metadata.

Source

Thrown at packages/utils/src/ar/cpio.ts:152

			devMajor: 0,
			devMinor: read16(bytes, offset + 2),
			inode: read16(bytes, offset + 4),
			mode: read16(bytes, offset + 6),
			nlink: read16(bytes, offset + 12),
			mtime: read32Words(16),
			nameSize: read16(bytes, offset + 20),
			fileSize: read32Words(22),
		};
	}

	requireRange(bytes, offset, offset + 6, "magic");
	const magic = String.fromCharCode(...bytes.subarray(offset, offset + 6));
	if (magic === "070701" || magic === "070702") {
		requireRange(bytes, offset, offset + NEWC_HEADER_SIZE, "new ASCII header");
		const field = (index: number, name: string): number => parseDigits(bytes, offset + 6 + index * 8, 8, 16, name);
		const checksum = field(12, "checksum");
		if (magic === "070701" && checksum !== 0) {
			throw new ArchiveError("Invalid CPIO archive: newc checksum field must be zero");
		}
		return {
			headerSize: NEWC_HEADER_SIZE,
			alignment: 4,
			inode: field(0, "inode"),
			mode: field(1, "mode"),
			nlink: field(4, "link count"),
			mtime: field(5, "modification time"),
			fileSize: field(6, "file size"),
			devMajor: field(7, "device major"),
			devMinor: field(8, "device minor"),
			nameSize: field(11, "name size"),
			checksum: magic === "070702" ? checksum : undefined,
		};
	}
	if (magic === "070707") {
		requireRange(bytes, offset, offset + ODC_HEADER_SIZE, "portable ASCII header");
		const field6 = (fieldOffset: number, name: string): number =>

View on GitHub (pinned to 9690622007)

Solutions

1. Regenerate the archive in the intended format: use cpio -H newc (checksum 0) or -H crc (magic 070702) as appropriate
2. If CRC verification is wanted, rewrite the archive with magic '070702' so the checksum is honored instead of required to be zero
3. Zero out inconsistent checksum fields only if you control the writer and know verification is not desired
4. Compare output of `cpio -itv` against your writer to confirm the header layout

Example fix

// before: writer stamps newc magic but fills checksum
header.write('070701', 0, 'ascii');
header.write(checksum.toString(16).padStart(8, '0'), 6 + 12 * 8, 'ascii');
// after: keep checksum zero for newc, or use crc magic
header.write('070701', 0, 'ascii');
header.write('00000000', 6 + 12 * 8, 'ascii');

const head = Buffer.from(new Uint8Array(await source.slice(0, 110)));
if (head.toString('ascii', 0, 6) === '070701') {
  const checksum = parseInt(head.toString('ascii', 6 + 12 * 8, 6 + 13 * 8), 16);
  if (checksum !== 0) throw new Error('newc header carries non-zero checksum; expected 070702 (CRC) format');
}

try {
  const entries = await readCpio(source, options);
} catch (err) {
  if (err instanceof ArchiveError && err.message.includes('checksum field must be zero')) {
    // rewrite archive with -H crc or regenerate as plain newc
  } else throw err;
}

When it happens

Trigger: Calling readCpio/readRpmArchive/entries on an archive whose headers use magic '070701' with a populated checksum field — e.g. an archive written as CRC format but with the magic bytes of plain newc, or bytes patched/corrupted in the checksum field.

Common situations: Custom writers that always emit the checksum (copied from CRC-mode code) while stamping the 070701 magic; manual byte patching; tool-version mismatches where the CRC variant was intended (the file should then use magic 070702).

Related errors

• CPIO member '${memberPath}' has an invalid CRC checksum
• Invalid ARJ basic header CRC32
• Invalid ARJ extended header CRC32
• Invalid CAB archive: CFDATA block ${block} checksum mismatch
• Invalid XZ stream: footer CRC32 mismatch

AI-assisted analysis of can1357/oh-my-pi@9690622007 (2026-08-31). Data as JSON: /api/errors/e21593e66207f230. Report an issue: GitHub.