Unstable WiF on Ultimaker S5; recommend updating connman to 1.36

[Thieuzor]

We have also seen the issue, reported here at the company, with Wi-Fi getting disconnected frequently and potentially have found a solution.
We have many Wi-Fi deployements with embedded Linux nodes (debian) and, as for the Ultimaker, we use connman to manage our network connections.
Until recently, we used debian stretch which comes with connman v1.33 and also noticed frequent Wi-Fi disconnects that couldn't be recovered by connman.
After updating to Debian buster, which uses connman v1.36, we noticed that most of our Wi-Fi problems disappeared.
Is it a possibility to also update the connman version to 1.36 in the Ultimaker firmware?
Note that we also identified other Wi-Fi related issues caused by the module firmware/driver and wpa-supplicant when roaming inside an SSID.

[robinmdh]

We will be working on a Debian upgrade to buster in the coming months, there are so many changes that taking the connmann version that indeed has a whole bunch of fixes in it separately from the whole release doesn't make sense (or we might have done that earlier).
We are very much aware of the issues and (some of) the fixes but haven't had/been given the time to work on upgrading Debian yet.
I'd be interested in the other issues you've identified, though hopefully roaming printers will be a literal edge case in the case of printers (as in printers sitting on the edge between to ~ equally powerful/near access points).
The whole upgrade is more than just connmann of course.

Thanks for the bug report!
As a member of the firmware team I am not used to getting them outside of the forum because the firmware is still sadly(to me personally) mostly close source, thankfully @nallath pointed this out to me, I'll try and update this wen the release fixing this is imminent.

[Thieuzor]

Thanks for your reply. Glad to hear you are working on a fix.
W.r.t. to the other issues, they are driver/firmware related for our Wi-Fi module. For security reasons we prefer not to disclose the exact part number.
In short, when scanning for APs in the same SSID, the driver/firmware sporadically returns a BSSID of 00:00:00:00:00:00.
If wpa_supplicant decides to roam and connect to this BSS, wpa_supplicant gets stuck in a deadlock state. It can however recover after we request another scan (has to be done "manually" via DBUS).
Note that our nodes are also stationary.
We quickly searched which Wi-Fi module is used in the Ultimaker (WUBA-171GN) and you are using a different chipset (Atheros AR9271).
If our information is correct , you will probably not encounter the same problem.