add BLE issue comment

src/platform/nrf52/NRF52Bluetooth.cpp

@@ -274,6 +274,24 @@ void NRF52Bluetooth::setup()
     Bluefruit.Periph.setDisconnectCallback(onDisconnect);
 
   
+    // Do not change Slave Latency to value other than 0 !!!
+    // There is probably a bug in SoftDevice + certain Apple iOS versions being
+    // brain damaged causing connectivity problems.
+
+    // On one side it seems SoftDevice is using SlaveLatency value even
+    // if connection parameter negotation failed and phone sees it as connectivity errors.
+
+    // On the other hand Apple can randomly refuse any parameter negotiation and shutdown connection
+    // even if you meet Apple Developer Guidelines for BLE devices. Because f* you, that's why.
+
+    // While this API call sets preferred connection parameters (PPCP) - many phones ignore it (yeah) and it seems SoftDevice
+    // will try to renegotiate connection parameters based on those values after phone connection.
+    // So those are relatively safe values so Apple braindead firmware won't get angry and at least we may try
+    // to negotiate some longer connection interval to save battery.
+
+    // See https://github.com/meshtastic/firmware/pull/8858 for measurements.  We are dealing with microamp savings anyway so not worth
+    // dying on a hill here.
+
     Bluefruit.Periph.setConnSlaveLatency(0);
     // 1.25 ms units - so min, max is 15, 100 ms range.
     Bluefruit.Periph.setConnInterval(12, 80);