X40 Ultra, carpet detection triggers wrongly after update

[hsanjuan]

Are you already using Valetudo?

Yes, for a long time

Your questions

I updated my Dreame X40 Ultra recently (valetudo and firmware). I have observed a degradation in the behaviour which consists in the "carpet detection" being triggered at wrong places:

• Side brush stops and mops are lifted, suction increases.
• Happens for a short time, then continues normal, as if it had seen a few centimetres of carpet.
• Actual carpets are correctly detected. I'm using "Detach mop" mode, so it will leave carpets for the end.
• When mopping, circling around the real carpet, when it encounters it, does not work well. It circles around it but very inaccurately, as if the edges were not detected properly. Before the upgrade, it went around accurately.
• When mopping, every "carpet detection" event means the robot tries to go around it, resulting in a very messy cleaning path.
• I cleaned sensors etc. the robot is cleaning wooden floors, but I found no pattern in the floor that might trigger it. No obstacles are detected in those areas.
• I lowered the Carpet Mode Sensitivity from High to Low, to no effect at all.
• It is not clear to me if all these "mini-fake-carpets" are always in the same place. I am not sure.
• My second robot does not seem to display this issue at all (same model + versions).

It appears a problem with infrared sensors was fixed in the latest firmware release, but I'm not sure it plays a part here. Any suggestions as to what to do or further debug are welcome. Perhaps there is a faulty sensor? Is there a way to check that?

[hsanjuan]

Ok, seems some people suffered the exactly same problem upon upgrade... so it is a firmware issue:

https://www.reddit.com/r/Dreame_Tech/comments/1hj3xy9/x40_after_update_to_439_1652/

One comment says it is related to "stain detection". This is a quirk that will be supported in the next release so looking forward to see if the issue gets fixed then. I will update with the result.

[hsanjuan]

If anyone lands here, I ended up downgrading to firmware image 1543, which works perfectly.