Firmware Version 1.0.2 incorporates the following fix.
1. Fixes an issue, in which the modeling flash may fire when the modeling flash setting is set to [Disabled].
If the flash's firmware is already Version 1.0.2, it is not necessary to update the firmware.
Preparations for the Firmware Update:
In the folder you downloaded are the firmware (EL110200.SFU / file size: XX,XXX,XXX bytes) and instructions on the firmware update procedures (a PDF file in five languages: Japanese, English, French, Spanish, and Simplified Chinese). Before starting the firmware update operations, please be sure to carefully review the instructions to confirm your understanding of the firmware update procedures.
Firmware download link:
https://www.canon.com.au/speedlite-flashes/speedlite-el-1/support?option=drivers