Crome is a popular ROM editing and tuning suite for OBD1 Honda ECUs. While the base software supports standard fuel and ignition tables, advanced features—such as launch control, full-throttle shifting (flat foot shift), and boost scaling—must be added via external plugins.

The Add Extra Features plugin (addextrafeatures.cpf) is one of the most common packages used to patch standard ROMs with these options.

Step 1: Place the Plugin File in the Crome Directory#

Crome plugins use the .cpf file extension. To be recognized by the software, these files must reside in Crome's local plugins folder.

1. Download the addextrafeatures.zip package from an authorized Honda tuning archive.
2. Extract the ZIP file contents.
3. Copy the addextrafeatures.cpf file and paste it into Crome's installation plugin directory. By default, this is located at: C:\Program Files (x86)\Crome\Plugins\ (on 64-bit Windows systems)

Note: Historically, legacy Crome plugin archives were password-protected to prevent corruption. If prompted during extraction, use the standard Crome installation password.

Step 2: Register the Plugin in Crome#

Once the file is in the directory, you must register it in Crome's settings interface:

1. Launch Crome.
2. In the top menu, navigate to Plugins -> Install New Plugin...
3. In the file explorer window that appears, navigate to Crome's Plugins directory.
4. Select addextrafeatures.cpf and click Open.
5. Verify that the plugin appears in the list of active plugins.

Step 3: Patch Your ROM BIN#

After registration, you must apply the plugin patches to the specific ROM file you are editing.

1. Open the desired OBD1 .bin file in Crome (typically a stock P28 or P30 ROM).
2. Navigate to Plugins -> Enhancements -> Add Extra Features.
3. A wizard dialog will appear. Click Next to run the code injection script.
4. Once the patching process finishes, the new parameters will be added to the ROM.
5. To configure the newly added parameters (such as launch RPM limits or boost cut pressures), go to the Options menu or access the relevant table tabs in Crome.