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screwdriversteve avatar image
screwdriversteve asked

Cerbo gx crashing garmin network

Hello all

I've been struggling for some time now trying to get my GX device connected to my Garmin Network. I think I have read all of the other posts around this question so forgive me if I miss the answer in another thread. If I plug my GX device into my Marine Network I can see it on one helm and everything appears to be working fine. I can see the GX device on active captain connected to the Wi-Fi on the boat as well as when I connect to the Garmin Wi-Fi. When I power down the Garmin equipment after leaving the boat and return the system will not boot up and I get a Garmin Network recovery screen. I have to power down the system disconnect the GX device and boot it back up to get it to work.

I have 3x 8600 series displays along with one 7-in display networked together. Using both the Garmin Network and nmea2000.

connected to the GX device

- Quattro inverter charger

- 2 victron solar controllers

- Smart shunt

- NMEA2000 Network

The GX device is connected to the Wi-Fi network on the boat and is communicating out onto the internet just fine. I have tried this configuration using the Garmin Poe isolator and the results are the same. I have a little bit of network experience but this level of troubleshooting is beyond me. It seems to be that there is a conflict in how the network addressing is being done when the system is booted.

When the GX device is independent from the Garmin Network both Networks perform flawlessly.


Any assistance would be greatly appreciated

cerbo gxmarine mfd appgarmin
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3 Answers
mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi,

We spoke to Garmin Support:

The recovery loader typically is shown if pin 4, 5, 7 and 8 of the Ethernet cable are used.

Garmin uses these pins for internal purposes. The PoE isolator terminates those pins. Could you double check if those pins are used?

Or perhaps the cable is not properly crimped? At least if you are using self made cables.

Have you also tried to replace the cable from the GX to the Garmin network?

https://www.garmin.com/en-US/p/782081/pn/010-10580-10

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mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hi,

That must be annoying!

Though I’m not a Garmin networking expert - I don’t know what could cause them to not boot, and haven’t heard about this issue before, herewith some tips and ideas that might help someone with more Garmin experience to sort this out with you.

I checked our notes, and last time we checked, the Garmins run their own DHCP server. Meaning that it should not be in a network with its own DHCP server: are you really connecting only the Cerbo into the network? Or is there then also a router connected (with dhcp service).

Perhaps a drawing helps.

And can you share screenshots or photos of the Ethernet menu page in the Cerbo, both when working OK and when not working OK; as well as a photo of the error on the Garmins. Does it give any details?



Ps. GX devices do not have a built in DHCP server.




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screwdriversteve avatar image screwdriversteve commented ·

Hello Mvader

I replied a couple of days ago but I see my comment didn't stick. Apologies I knew to the layout and hopefully this one sticks around. Your idea of DHCP made me think my GX device is connected to my starlink via Wi-Fi so I'm wondering if the GX is bridging the networks and the DHCP server in the starlink is fighting with the Garmin. I shut down the starlink and was able to repeat the error. So this is not the issue.

When the error occurs the GX shows the ethernet as unplugged so it's not even getting any messaging at all. It's like the Garmin unit completely misses booting it's OS and is sitting at a before the OS is loaded.

This is the GX ethernet screen when I plug it in after the Garmin has been booted and everything functions.

screenshot-20240628-132344-chrome.jpg


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mvader (Victron Energy) avatar image mvader (Victron Energy) ♦♦ screwdriversteve commented ·
Hey, thanks at helps.


The GX doesn’t do any network bridging. It looks to me like the GX inadvertedly sends some message causing the Garmin to think a recovery is wanted.


I’ll post this link to our Garmin contacts and see what they think.

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jay-1 avatar image
jay-1 answered ·

No thanks to Garmin tech suppiort, I finally found a solution to the "discovery loader ready" message during boot up of my GPSMAP 1243 and 743 on the garmin marine network with CerboGX connecrted through GMS10 network switch.

The message is indeed caused by Garmin's use of pins 4,5,7 and 8 for device powerup in a way that conflicts with the CerboGX. If I cut the network wires to these pins, no error during bootup. (alternatively Garmin says using their $63 POE blocker adapter would block these pins.)

The second thing I painfully discovered is the cable connecting the CerboGX and the Garmin network needs to a straight patch ethernet cable. All my Garmin cables were "crossover cables" which would not work with the CerboGX. The message said "searching for device". So I just used a regular ethernet cable instead.

Finally everything works.

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Related Resources

Cerbo GX product page

GX family product range

Cerbo GX & GX Touch datasheet

Cerbo GX Manual

Venus root access document

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