U400 needed more app testing and optimization

General
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Hey friends,

So I got my u400 today and set-up was a breeze it literally took 5 minutes to install very easy installation. BUT the app setup is a total nightmare. I couldn’t get it to connect to my phone through Bluetooth. I couldn’t add a user or admin, it just kept failing. It wouldn’t update either kept saying lost Bluetooth connection and lastly I can’t get it to connect to any of my Aqara hubs. So ya the software side needed more time to get right. But then again the Aqara app hasn’t been really great ever since the AI and automation 2.0 updates. Ever since those updates all my devices seem to always be broken because of it. I wish I could share more about my experience, but unfortunately my u400 won’t connect to any Aqara hubs. So I can’t really set up anything or see how the lock performs, so until they get rid of all these bugs and problems, I’m just going to take it back down and just put my u50 back up. Which kinda sucks. But I really do not feel like fighting the u400 and the aqara app, so I’ll just wait.

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Dear User,

We sincerely apologize for the frustration you may have experienced. Your feedback is important to us, and we are committed to continuously improving the app interface and the binding experience.

Bluetooth Connectivity Optimization We have identified a known issue where entering the settings or trying to add a hub before a stable connection is reached can cause performance issues.

  • Pro-Tip: After opening the app, please stay on the U400 main page for a moment to let the Bluetooth connection stabilize before navigating to other menus. We are working on a fix to improve this in the next software update.

Common Binding Issues (Aqara Home) If you are having trouble connecting to the Aqara Home app, please check the following:

  • Region Settings: Ensure your Aqara account region is set to a supported location: United States, Canada, Singapore, Australia, or New Zealand.
    • Path: Profile > Settings > Region.
  • Avoid Scanning the Wrong Code: When scanning the Aqara MagicPair code on the lock, use your finger to cover the Matter Pairing Code next to it. This ensures the app reads the correct code for the Aqara ecosystem.

For a detailed, step-by-step binding guide, please refer to our community post: Guide: Setting Up Your Aqara Smart Lock U400

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Hi thanks for the response so I eventually got the u400 configured, I just gave it some time and eventually the bt started working like you mentioned. But I’m still having problems with the u400 disconnecting from my m3, but to be honest I think my m3 is faulty because it’s always having problems with bInded devices going offline. And so I have to factory reset it quite of bit to get things working again. I haven’t had any problems with 3rd party binding with smart things or apple home. As long as it works fine with smart things I’m good because that’s how I run my automations for my u50 and now the u400. I would rather use Aqara app for automations but for some reason I’ve never been able to get automations to work with my u50. But I honestly think it’s because of my m3 hub is why automations have never functioned on my u50.

But now that I got the u400 running the only problems I’m having now is charging is very slow and doesn’t update in the Aqara app or 3rd party app. 2nd problem is Bluetooth only connecting if I’m a foot away. 3rd is gyro is not working so it’s always saying status unknown but that don’t bother me because the gyro never worked on the u50. 4th problem is adding passwords and fingerprints keeps failing, Other than those problems. I really like the u400 and I’m confident you guys will fix these problems or else wouldn’t buy Aqara products but I seriously love everything about Aqara and yes you guys aren’t perfect but who is?

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Hi there,

It is a pleasure to see that you have successfully bound your U400 to the Aqara Home app!

Regarding the Hub M3 offline issue, we are actively investigating this and are currently attempting to reproduce your specific usage scenario in our lab test. To help us identify the root cause, could you please confirm the following:

  1. After you bind the U400 to the M3, how long does U400 stay online before going offline?
  2. What is your current M3 firmware version?
  • (Path: Hub M3 > Settings > Tap on Hub M3 to enter Device Information page)
  1. Action Item: Please report these connectivity and automation issues directly to our customer service team. Our development engineers will track this feedback to optimize performance.

Regarding your U400 Questions:

Question 1: Charging Issues & Firmware Fix The charging issue you described is a known bug in firmware V3.1.0.4 (specifically, the inability to fully charge via the rear Type-C port and slow battery level synchronization).

We have resolved this in Beta firmware V3.1.0.6. We highly recommend updating to this version by following the instructions provided by Kinsey at the beginning of this post: Aqara Smart Lock U400 – Progress Update | V3.1.0.7 (Jan 16) - #2 by KinseyCreateGoods

Reference: Charging Methods We recommend two methods for charging (both require a 5V 2A source):

:battery: How to Charge Your U400

We recommend two convenient methods for keeping your lock powered. Both require a 5V 2A power source:

Feature Method 1: On-Door Charging Method 2: Battery-Only Charging
How-To Connect a USB-C cable to the port at the bottom of the inner lock body. Remove the Li-ion battery and connect the USB-C cable directly to it.
Time ~14 hours to full charge. ~7 hours to full charge (Faster).
Pro-Tip Place a power bank in a small bag and hang it on the handle for easy charging. Note: The lock will not work while the battery is removed. Always carry your physical key as a backup!

Charging Indicator: The light on the battery will turn green when fully charged. You can monitor live battery levels and charging status in both the Aqara Home and Apple Home apps.

Question 2: Bluetooth vs. Matter For the Smart Lock U400, Bluetooth is primarily designed for initial setup, local settings configuration in the Aqara Home app, and close-range communication. For daily usage and remote control, we recommend to rely on Matter-over-Thread for the best experience.

Question 3: The “Unknown” State The “Unknown” lock state generally only occurs in three specific situations:

  1. After Door Lock Calibration.
  2. After a firmware update.
  3. After removing/reinserting the battery or a power cycle.

How to Fix It: Fully open the door, then close it from the inside and lock it. This extra step ensures correct gyroscope detection.

Note: The gyroscope algorithm on the U400 is significantly improved compared to the U50. In our internal lab tests for the “Auto-lock on close” feature, we achieved a 100% success rate over 100 cycles.
Question 4
Question 4: Video Request Could you please provide a video recording of the failure? This would be incredibly helpful for our engineers to analyze the specific cause and provide you with a solution as soon as possible.

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Hi thank you so much for all these suggestions, I absolutely love and appreciate it. So I have good news, I did a power cycle to my router and all my Aqara hubs and I also did a reset on my smartthings hub and everything seems to have settled in and is working so far. After resetting smartthings hub I actually got more settings to appear, like creating a passcode and I think UWB as well?. Those features and settings did not pop up when I originally had binded it to smart things. So everything looks to be synchronizing like the battery is showing the proper state of charge. The only two things that I have noticed is my auto Lock automations didn’t run because the u400 wasn’t responding to the hub and the other thing that’s still not working is the gyroscope it works for a while and then it goes back to unknown status in the aqara app I have done a couple of calibrations and I have updated the u400.I’m going to include some pictures and videos on one of the pictures there is a setting called connection path is that UWB for smartthings?


Screenshot_20260123_010927_SmartThings
Screenshot_20260123_010927_SmartThings1080×2212 189 KB

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Dear User,

Apologies for the delayed reply.

Automation issue

  1. How did you configure the automation? Please specify the IF condition and the THEN action.
  2. In which ecosystem did you create the automation? How far is that ecosystem’s gateway/hub from the lock, and are there any obstacles (walls, metal doors, etc.) between them?

Door-state / gyroscope issue
If the lock shows “Unknown” door state, please recalibrate the lock in the Aqara Home app and follow the on-screen instructions to restore door-state sensing. The “Unknown” state commonly occurs for one of the following reasons:

  • Firmware update to the lock.
  • Lithium battery removal and reinsertion.
  • Calibration was not completed correctly.

Finally, how is Auto-Lock configured on your device? Is it set via Samsung, via Aqara’s Auto-Lock on Close, or not enabled at all?

UWB feature in SmartThings ecosystem
We currently have not supported the UWB unlock feature in SmartThings yet. For the latest official updates and detailed information, please visit our official website or refer to the firmware update release notes.

In the meantime, you may also send a description of the issues you encountered to support@aqara.com. Our technical support team and developers will review your case and respond as soon as possible.

Please feel free to contact us at any time. I’m appreciate to hear that you were able to resolve the issue and get the lock working. :raised_hands: