Sorry please for a silly question maybe…Will Up Board for this specific input work with HQP Desktop backend NAA or only HQPe?
Edit, found this one in Desktop thread HQPlayer Desktop thread - #62 by Chunhao_Lee
Edit2, added only overlay so far. have it playing with 44.1 at hqp desktop via class 2. there is a otg overlay in overlay folder too. will try that too. right now feeding from ipad pro, hdmi cck to pi 4 usb c
Edit03, it is playing via Pi4. Not stable currently. Using HQP Desktop. No edit on hqplayerd.xml. Does xml exist on NAA OS??
Yep, using 44.1 input for audio interface setting at HQP Desktop. HQP shows in „Format:“ correct samplerate. So, switches there correctly. Always on 44.1 for input. But, but, but, not stable have drop outs…. @dabassgoesboomboom
Edit04, it is pretty stable now. HQP shows automatc switching 
Used Pi4 is a pretty new one.
not using otg overlay, but the one mentioned here. however no edit at hqplayerd.xml. dont have that on naa os for pi 4? not using ramfs image please. no hub, as hdmi cck has power input option.
+++ However so far would not recommend as bit special. However once it plays 
+++
Edit, using Lightning CCK with Powersupply did not work. Guess you need the hub like @Chunhao_Lee is using.
Myself working with one on iPad Pro 12, Gen 4, USB-C Digital AV Multiport Adapter - Apple
@Michael_Grant , this seems to work but… Up Board prob much more stable for samplerate switching.
Works e.g. with Qobuz iOS App too, but partly NAA OS reboot required of little Pi.
CAUTION ###### Be super careful with this experiment, when switchin iOS Apps. You risk terrible noise. Better to stop HQP audio input and switch app and enable HQP then again. Sp, please this a experimental solution only please so far.
Edit; did hook it up to my “better” chain now. No issues at all anymore with stabilty, whatever i do. whatever i am switchting to on iOS. However still be careful with this approach please.
Edit; HQP automatic Filter switching (for 1x and Nx) works with automatic sample rate switching too
Edit: Atmos is working too. iOS AM App even shows the Atmos logo when playing Atmos. And listening test passed succesful too. @jussi_laako @Chunhao_Lee When playing an Atmos track from AM, the automatic sample rate switching seems not to work anmore, at least the shown format in HQP Desktop.However HQP plays the Atmos track as Atmos. It shows as input the last choosen stereo sample rate instead of the samplerate of the Atmos track. No Atmos logo at HQP too.