Converting Humminbird 5xx, 7xx, 99x, 119x, Helix sonars to cxi version

Below is detailed walk-through allowing everyone to convert Humminbird 5xx, 7xx, 99x, 119x, Helix sonars from ci to cxi (international) version. I don’t know why Humminbird decided to have American and International versions of its devices. Hardware and firmware are absolutely the same for both. However, price difference anyway urged people to buy them in US and allowed other people to earn money hacking firmware around. This method doesn’t actually require any reverse engineering, and everybody can do it. Since I’m making this secret public, Humminbird might decide to close this “feature” for new devices in the future. However, currently there is not much commercial interest to keep it in secret.

Long story short. Each device has its own internal model identifier. This is for firmware to “understand” which device it is since many parts of code are similar for different series. This identifier is SMDL. You can open profile.txt (name can vary) file from SD card, that was inserted to device to find its value. Here is example for 999ci:

SMDL;0x00000194

This (0x194) is number 404 in hexadecimal system. There is no way to change SMDL parameter through modifying the file’s content. Every time it’s returned to previous value. The whole task is to change this parameter without altering firmware. This is possible to do through demo-mode (or simulator).

For this all you need to do is to create on SD card file with name POSDemo.txt (case-sensitive!). Put the following in there:

SET SMDL 405

After this insert the card to the device and boot it in simulator mode (without transducer plugged in) . If mode doesn’t start, reset the settings to default and make sure it’s enabled in settings. This script will run in demo mode and all changes made by it will remain after restart.

Above 405 value is for 999 cxi. For every model you need to use different number. In order to find it out, you need to use parameter for ci in Hex format and add 1. For example, 0x194 = 404 (999ci) + 1 = 405. You can use many online sites for conversion. You also might ask for help your computer geek kid ;).

Below are known values for “international” SMDL.

P. S. If you find this information useful in a commercial way, feel free to donate some of earned/saved money to charity fund of your choice