Your computer should have a JAVA environment, and the modified rom should be compressed into zip format. Then download the signature tool, open the signature tool, and click Sign. An option will appear and click.

After clicking, a dialog box will appear. Click Select. Locate the ROM to be signed. In the lower right corner of the window, there is a file selection type. Select zip. Select the ROM to be signed, click Sign Now, and a dialog box will appear. This dialog box prompts for the location of the signature file. Here, add something. Zip, the file will be automatically saved in zip format. Select and click Sign Now again. After clicking, it may show no response, so leave it alone. It took a little long to sign the bill at the first run, but it was shorter later. So the signature is completed and you can brush the machine.