[HL7688] Firmware Update via UART from Embedded Linux (Busybox) — Procedure & Tools?

IoT Modules Legacy HL Series
1

Hardware & Environment:

  • Modem: Sierra Wireless HL7688

  • Host Processor: AM335x ARM Cortex-A8

  • OS: Linux 4.4.19, Busybox environment

  • Interface: UART (host processor ↔ modem), no USB available on this platform

  • Current Modem FW: 2.15.1.0.151600.201809181425.x7160_1

  • Target FW: Latest available for HL7688

What I need:

I need to update the HL7688 modem firmware over UART from an embedded Linux/Busybox environment. USB is not an option on this platform.

Specific questions:

  1. Firmware package — I don’t currently have the .cwe/.spk package. Where can I download the latest HL7688 firmware? (I have access to the Sierra Wireless Source portal.)

  2. Flashing tool — Is fwdwl-lite or nufwdwl-uart the right tool for UART-based flashing on an embedded Linux host? Are pre-built ARM binaries available, or will I need to cross-compile for arm-linux-gnueabihf?

  3. Download mode — What is the correct procedure to put the HL7688 into firmware download/QDL mode over UART? Is AT!BOOTHOLD supported, or is a hardware reset sequence required?

  4. UART port — Should I be using the modem’s DM port or the AT command port for the flashing process?

  5. Baud rate — What baud rate should be used during the UART flash procedure?

Any pointers to AN or documentation specifically covering UART-based firmware update for the HL7688 on embedded Linux would be greatly appreciated.

2

have you tried download via Airvantage platform?

BTW, I saw there is AT command to download by XModem protocol:

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3

@jyijyi Thanks, I was able to successfully update the modem firmware using the AT commands. Below are a few observations that were not mentioned in the datasheet, or that I discovered during the process:

  • AT+KSLEEP=0 — Sleep mode must be disabled; otherwise, the file transfer will not work.

  • AT+WDSI=4095 — This enables all notifications.

  • After the file transfer, I did not receive the expected +WDSI: 3. I manually issued AT+WDSR=4 and waited until +WDSI: 16 appeared.

This topic was helpful → HL7688 Firmware Archive

However, I only see the firmware version RHL7688.A.2.15.1.0.151600.201809181425.x71601signed_DWL.dwl available for download(Already my current version). Are there other versions I can test—for example, to perform upgrade/downgrade validation?

The available file is quite large (~20 MB) and takes a long time to transfer over UART. Are delta-update files available instead? If so:

  • Where can I obtain them?

  • How should they be flashed onto the modem?

4

have you tried higher baud rate and see if it speed up the transfer?

You can also try Airvantage to do firmware upgrade

5

Higher baud rates would certainly improve the firmware transfer time, but due to design constraints I am limited to using 115200. Using AirVantage isn’t an option for my setup, as the firmware update for this modem needs to be fully controlled by my own application.
Are delta-update files available? If so:

  • Where can I obtain them?

  • How should they be flashed onto the modem?

6

what is the current firmware version of your modules in the field?
Are you going to upgrade to 2.15.1.0?

BTW, did you report this request to your distributor?