I am also testing this with the nRF54L15 and I am able to get it functioning with the iOS 27 public beta 1. However it also seems to require bonding as @dinesharjaninordic mentioned. Is that going to be a requirement vs just pairing? Also is AccessorySetupKit required to be used before CS? My app connects with CoreBluetooth and bonds the accessory without ASK. In that app, startChannelSoundingSession fails with CBInternalErrorDomain code 10 ("Operation is not allowed") even though the device is bonded. It only begins working after a different app pairs the same accessory via AccessorySetupKit. From that point on, CS works in my non-ASK app.