I thought I’d post this up in case it helps someone else.
On Saturday I decided to update the cartography on my Zumo XT and PC. I’ve undertaken this task several times before, using the same PC and router, so expected no issues.
I fired up Garmin Express and was alerted to the availability of version 7.16.3.0 so installed that, then connected my Zumo XT. There were several updates available including a Time Zone update and Cyclops Safety Cameras update so I installed all those before shutting down Express completely and disconnecting and rebooting the Zumo. I then reconnected it to the PC and fired up Express again.
I selected the map update and the update started. After about 10 minutes I noticed a red error bar on Express informing me that the update had failed, so I disconnected and reconnected the Zumo and restarted the update which ran for around 15 minutes before erroring again. I repeated the disconnect and reconnect of the Zumo, quit and restarted Express and restarted the update for a third time which then ran to completion without issue.
After disconnecting and restarting the Zumo, I checked that the updated cartography was all present and correct and then reconnected it to the PC to update the cartography for use with BaseCamp. And that’s when the real trouble started.
After selecting Install to Computer and accepting the Terms and Conditions, Express displayed the Applying Changes panel together with the Download Rate and Time Remaining. All was well until the process stalled at 44.3% complete when the Download Rate disappeared and the Time Remaining changed to Unknown. I closed and quit Express before re-starting it and initiating the Install to Computer again. The Applying Changes panel zipped quickly up to 44.3% as Express confirmed the integrity of the files already downloaded, then came to an abrupt halt and proceeded no further.
Bearing in mind that I’d had the issue with the update to the Zumo, I pondered whether there was an issue with the Garmin server(s). But also, I had updated Express so was that causing an issue? I had other things to do so drew stumps with the intention of experimenting further the next day.
Knowing that one of Garmin’s recommendations if a cartography update stalls using Express is to uninstall and re-install the application, I started off by doing that (including leaving the “remove all Express data” checkbox selected) on the uninstall. I then added back the Zumo as a device and started the cartography installation to the PC. Slightly to my surprise as I’d asked the uninstall to remove all Express data which I would have assumed to include incomplete update files, it once again zipped quickly up to 44.3% as Express confirmed the integrity of the files already downloaded, then came to an abrupt halt and proceeded no further.
At that point I decided to manually remove the folder 2024_10 from C:\ProgramData\Garmin\Maps\RMU\EU so as to force a full download in case there was an issue with restarting from a partial download. On restarting the install process the Applying Changes panel started from zero percent (good!) and proceeded normally as the download progressed until it hit 44.3% once again when it stalled. I was now fairly convinced that the issue was on the server side so decided to leave things until later on Monday by which time Garmin’s support staff would hopefully have checked logs and fixed whatever the error was.
So I have another attempt early this afternoon, after removing the 2024_10 folder again. Nope. Same result as yesterday: gets to 44.3% and stalls. It was then that I decided to check the router’s logs.
I use a Ubiquiti UDM router (which, BTW, is excellent) and have the Threat Management feature set to “Detect and Block”. On interrogating the logs I found that at precisely the time of each Express download stall the router had identified an event with signature “ET SHELLCODE Possible Call with No Offset TCP Shellcode”. Furthermore, this event was always associated with the same Cloudfare IP address. This had to be too much of a coincidence so I turned off the router’s Threat Management feature and tried the cartography update again. It worked perfectly!
I have no idea why the UDM router is identifying a false positive threat when attempting the cartography update to the PC, as it has never done so before. Whether it’s related to the latest version of Express, something about the CN EU 2024.10 data set, or it’s something to do with the current version of the UDM’s threat detection engine I have no idea, but if anyone else is experiencing map install issues and is using a Ubiquiti router, it’s worth checking the router’s logs.