Intel HEX & S-record Image Audit

It reads a .hex, .ihex, .s19, .s28, .s37, .srec or .mot file and runs 16 checks over it. It recomputes the two's-complement checksum of every Intel HEX record and the 0xFF-minus-sum checksum of every S-record, compares the byte-count field against the bytes actually present, maps every absolute address the image writes, and reports each defect with its line number.

Embedded firmware engineers and build engineers who ship a .hex or .s19 image to a flash programmer, a bootloader or a contract manufacturer. It is aimed at the moment an image is merged, hand-patched or regenerated by a script, which is where stale checksums, overlapping records and appended data after the EOF record come from.

Online hex viewers render the records; they do not recompute the checksums or map the address space. A chatbot cannot verify a checksum over bytes it never sees, and it will not notice that two records in a merged image write the same absolute address. Your programmer will only tell you after it has already refused the file, at the bench.

Auditing one image is free and complete: all 16 checks, in the editor or in the browser, with no key and no truncated output. The licence adds a different job - auditing every image in a build output folder in one pass and exporting a dated Markdown audit report you keep as release evidence.

Embedded firmware contract work is commonly billed at $90 to $150 an hour, so one hour spent reading records by hand costs more than the licence. The other price is the one you pay at the flashing station: a batch programmed from an image whose records nobody recomputed.