SMALL BYTE EDITS · CHECKED BEFORE APPLYING

Binary Byte Patcher

Replace known bytes at exact offsets in a separate file copy. Validate expected original bytes, reject overlapping edits and save a source-hash-bound patch project.

1. Source & edits

Original file (16 MiB maximum)

No file.

Or open a saved patch project

No imported project.

One offset | expected hex | replacement hex per line

Decimal or 0x offsets · 1–200 non-overlapping patches · 1–256 bytes per patch · equal-length replacements only · 60-second job limit.

2. Review every byte change

Choose a source and enter expected and replacement bytes.

Offset	Hex offset	Expected bytes	Replacement bytes

Original & patched checksums

Byte edits can break formats, checksums, signatures or application behavior. This tool does not repair format structures or determine which edits are appropriate. It never executes file contents.

How to make a controlled byte edit

Use the Hex File Inspector to locate the exact original bytes.
Open the original and enter offset | expected hex | replacement hex. Expected and replacement lengths must match.
Preview the patch. Every expected byte must match and no patch may overlap another or extend outside the file.
Download the separate patched copy. Save a project if you want to repeat the exact edits on the same original bytes.

Projects and source checks

A reopened project requires the same original SHA-256 and size, then checks expected byte sequences again. Manually editing the patch text removes the imported source-hash binding; expected bytes are still checked. Files are not persisted automatically. No insertions, deletions, wildcard matching or executable launching is provided.

Use this for your own data files, fixtures and carefully understood format corrections. Hash matching is not proof of safety or authorization, and an exported project is not a digital signature.

Using Binary Byte Patcher

Apply a small, explicit set of byte replacements to a copy while preserving the original file length.

Choose the source and enter offset, expected bytes and replacement bytes.
Validate all patches and review the complete change table and SHA-256 hashes.
Download a separate patched copy or save a source-bound project.

Example

The sample changes Hello, world! to Jello, Earth! using two equal-length replacements.

Questions & answers

Can it insert or delete bytes?

No. Only equal-length replacements are supported, preserving offsets and total size. Overlaps, out-of-bounds edits and expected-byte mismatches stop the entire operation.

What does a saved project verify?

It stores original size, SHA-256 and explicit patches. Reopening requires the same original bytes. Editing patch text manually removes the imported source-hash binding while retaining expected-byte checks.

What are the limits?

Source files up to 16 MiB, up to 200 non-overlapping patches and 256 bytes per patch. Jobs stop after 60 seconds.

Does it change my original file?

No. The original is read locally and a separate patched copy is downloaded. No selected file is executed or uploaded for processing.

Can any format safely be patched?

Not automatically. Byte changes can invalidate internal offsets, checksums, signatures or application rules. The tool checks your byte instructions, not whether the result is a valid format.