Setting up GPS

Update the firmware then you should be able to set which speed genie screens display.

From http://mtbest.net/setting-up-navi-GT31.htm

Attention: the firmware upgrade procedure has changed to become compatible with all firmware versions (V1.2 V1.3 and V1.4) that are currently in use. New upgrade procedure is faster and safer for your GT31 than the procedure previously published on this website.

Before you begin your GT31 firmware upgrade, you need to identify which "V" version of the firmware is installed in your GT31. There are V1.2, V1.3 and V1.4 versions in use. Since Locosys no longer maintains V1.2, it is not provided here.

All V1.2 V1.3 and V.4 varieties of GT31 firmware provide exactly the same GPS-Doppler speed accuracy and performance, because they use exactly the same code and parameters for the SiRF3 GPS-engine inside GT31 (published here). Firmware versions downloaded from this website after V1.2B1405 (after 14 May 2009) provide SDOP data that is required for error-margin computations and Speed Records. Later versions include bug fixes and various User Interface improvements. Please read README file associated (and zipped) with a version to discover what changes were made in respect to previous versions.

The difference between V1.4 and V1.3 are a) different power-up boot kernel and b) different memory range for Data Logger. For this reason 2-file update is needed when upgrading to V1.4 from lower V versions. All new GT31s have V1.4 installed by default. Locosys states that "eventually" all GT31 units should have V1.4. Locosys also says that there is no need to upgrade to V1.4 if version that you currently use satisfies your needs.

0. Download the GT31 firmware:
GT31 V1.4: GT31_FW_V1.4B0803T.ZIP
GT32 (new twin-GT31) V1.4: GT31_FW_V1.4D0428T.ZIP (works on plain GT31 too)

GT32 is a new 50Hz instrument that combines gps-Doppler with inertial navigation technology. For details please see GT32-resource website.

1. After you downoaded the appriopriate ZIP file above, you need to "unzip" the content. The file with extension *.s is the firmware. V1.4 firmware has two *.s files, one firmware file and a GT31boot file. After unzipping, please read README and UPDATE-INSTRUCTIONS files
2. Install GT31Updater V0.71 or higher software, if not already installed (it is included in zip archive)
3. Install USB-serial driver from GT31 CD, if not already installed. The driver is necessary to communicate with GT31.
4. Clear GT31 Data Logger (DATA LOGGER>CLEAR>YES)
5. Turn your GT31 OFF
6. Remove the SD card and find a tiny sliding switch "inside the card slot" on the pcb, on "display side" of the card slot. The switch has a black lever and metallic body. The default position of the switch lever is labelled in white on pcb.
7. slide the switch lever using a match or a similar object away from the white mark
8. As a precaution, exit all Windows applications and disconect from Internet. Run GT31Updater V0.71 (or later). Select the correct COM port from the pop-up menu and choose "INTERNAL" mode. Then use "browse" function to select and load 2 files that you unzipped in step 1, one at a time:
a) V31BOOT_V4D.s (you only need to update this when upgrading to V1.4 from lower V versions)
b) V1.4 firmware
It may be necessary to quit and re-start GT31 Upgrader V0.71 after the first file update.
9. when Updater finishes, disconnect GT31 from USB cable, move the switch lever to its normal position, labelled white on pcb. Your GT31 should be ready to use. Power in ON, go to Settings and select Version. You should see the Version Number corresponding to the name of the file in step 1 and 8b.