DFU becomes significantly slower on Android 15

[Teruyama]

When performing DFU with the same Android device + nRF Connect on the same target device, the speed becomes significantly slower on Android 15.

The attached image captures the graph of DFU performed on the same device using Pixel 6a + Android 14 or 15, and the transfer speed is clearly different.

The device in use is an nRF52840. However, we have confirmed that the DFU speed decreases on other devices as well.
Both tests used nRF Connect version 4.28.1.

Is it possible to improve the speed by changing the settings in nRF Connect or the usage of the DFU library?

[Vidar Berg]

Hello,

Is your FW based on the nRF Connect SDK or the nRF5 SDK? In case it's the latter, please ensure the 'packet receipt notification' option in nrf connect -> settings -> nRF5 DFU options is disabled. If it is necessary to troubleshoot this further, it would be helpful to have a BT sniffer capture of the DFU transfer with Android 14 and 15.

Best regards,

Vidar

[Teruyama]

We are using nRF5 SDK version 17.1.
I tried disabling PRN, but unfortunately, it did not improve the issue.

[Vidar Berg]

Thanks for confirming. Are you able to provide a sniffer capture that shows DFU with Android 14 and 15? I have not seen any other reports of DFU being slower with Android 15.

[Teruyama]

I was able to capture the sniffer data, so I will upload it. Since this is my first time reviewing such data, I am not familiar with the content. Are there any noticeable differences between Android 14 and 15?
sniffer_20241001.zip

[Vidar Berg]

Unfortunately, the captures don't show the connections in DFU mode. Which version of the nRF5 SDK is the firmware you're upgrading from based on?