How do you patch an ips file to a gba file?

To patch an IPS file to a GBA file, you need a patching tool such as Lunar IPS or NUPS. Open the patching tool and select the IPS file as the patch and the GBA file as the target file. The tool will apply the changes from the IPS file to the GBA file, creating a new patched version. Make sure to keep a backup of the original GBA file in case you need to revert to it.