Apple devices with N1 WiFi chip experience very slow upload speeds with certain WiFi APs.
It looks like the N1 chip does not honour Maximum MPDU length parameter in WiFi Association responses, and even though the WiFi AP announces support only for small MPDUs (3895 bytes), N1 chip keeps aggregating 4 frames into A-MSDUs, creating frames with excessive length of 6178 bytes, which are not supported by the AP.
Older devices like iPhone 16 always respect Maximum MPDU lenght allowed by the AP and in the above scenario send A-MSDUs with maximal length of 3130 bytes.
APs which support larger MPDUs (7991 or 11454 bytes) work fine with Apple devices with N1 WiFi chip.
