What this patch tool does
Create or apply classic IPS patches locally with standard PATCH/EOF records, RLE application support, and optional final-size truncation/extension.
Format and input contract
Classic IPS uses three-byte big-endian offsets and two-byte record lengths. Phase 20 input/output remains capped at 8 MiB even though the format address space is larger. Generated patches avoid emitting records that begin at the reserved EOF marker offset.
Integrity and compatibility limits
Classic IPS provides no checksum of the source, target, or patch. The source file must be verified independently. This implementation does not claim IPS32 support.
Browser-local processing
When operational, Phase 20 reads only files explicitly selected in the browser, enforces bounded buffers, and does not silently upload patch inputs or outputs.