Here 4 GPS stuck ( white Light )

[Prince_Chauhan]

Hello Team, I am facing an issue with my Here4 GPS module connected via CAN UAV. The GPS shows a constant white LED and seems to be stuck in that state. When I connect it to the system, the GPS ID does not appear, and the module is not detected, so I am unable to configure or use it. I have checked the connection, but the issue persists. Could you please guide me on what the white LED status indicates and why the GPS is not showing its ID on the CAN bus? I am attaching photos of the setup and LED status for your better understanding. Thank you.

[Oliver_Papak]

SB_0000010 Mandatory Here4 bootloader update before further flight

BEFORE FURTHER FLIGHT Urgent Bootloader Update needed on Here4 If your Here4 doesn’t breath blue on boot, then you MUST do this bootloader update All Here4 users need to update the bootloader on their Here4 units BEFORE FURTHER FLIGHT. For units NOT showing blue breathing at boot The process for doing this update is as follows: Follow the steps here to update the firmware Here 4 Manual | CubePilot Once the Update is done, set parameter on Here4 FLASH_BOOTLOADER to 1 wait for either Bootloader Flash OK or Bootloader Unchanged message An updated bootloader boots with Blue Breathing at boot. It will breathe purple if CAN1 on here4(blue/white cable) is not connected or Cube is still booting, so to check best to unplug and plug Here4 without power cycling the Cube itself. Use the Blue/white Can cable on the here 4 to CAN 1 or 2 on the Cube carrier board For units already showing solid White LED (NOT breathing) If you have appropriate SWD connector (6pin JST SUR) to Here4 available, and are capable of doing a bootloader update. Follow the following steps: For STLink: Use this bootloader file and flash at address 0x08000000 For JLink: Use this bootloader file use JFlashLite to flash. Important: For users that are not capable of opening Here4 unit and updating using JST SUR and Debug probe to fix solid white LED, please contact your Reseller for further support. For units that are still healthy make sure to follow primary bootloader update method. Additional Resources: Batch Update Tool Here4 FW Release 1.15.0

[Fares (Dr. Fares Al Dhaheri)]

Very interesting case.

We recently noticed during some bench evaluations that CAN initialization behavior on Here4 can sometimes become inconsistent if the module experiences interrupted boot/update sequences or unstable power during startup.

A few things that were helpful during troubleshooting on our side:

• Verifying stable 5V rail during boot and avoiding voltage dips during initialization
• Testing with the shortest possible CAN wiring path initially
• Disconnecting unnecessary CAN peripherals temporarily during recovery attempts
• Verifying proper CAN termination before repeated boot attempts
• Allowing the Cube to complete full boot before reconnecting the Here4 during certain recovery scenarios

The solid white LED behavior definitely looks consistent with the bootloader-related condition mentioned above by Oliver.

Would be very interested to hear whether the module responds after the bootloader recovery process.

Dr. Fares Al DHaheri

Al-Etihad Industrials, UAE