How to update EM7305 Firmware?

How do I update the firmware?

I have download the Build4837-Approved-Only-7305-EXE.zip and Build4837-Approved-Only-7305-SPK.zip but can’t use ist.

C:\Users\Venue11\AppData\Local\Temp\FDT>fdt.exe -f 9999999_9903271_SWI9X15C_05.05.61.00_00_VODA-EU_005.024_000-field.spk
FDT version: 5.0.1501.1
Checking modem mode ...
Switching device to boot & hold mode ...

Firmware download failed.
Primary error code: 51 - Failed to switch device to BOOT&HOLD mode.
Secondary error code: 51 - Failed to switch device to BOOT&HOLD mode.
Device error code: 0x0 - Successful.
Total time elapsed: 1188 ms.
Press Enter to continue ...

Installed firmware:
Hersteller: Sierra Wireless, Incorporated
Modell: EM7305
Firmware: SWI9X15C_05.05.47.00

Have you tried with the One Click Tool (9999999_9903271_SWI9X15C_05.05.61.00_00_VODA-EU_005.024_000-field.exe)?
Please check if you have the latest drivers and that the modem enumerates correctly in device manager.
You can also try resetting the modem (AT!RESET) and then running the OCT.