OTA upload often fails when client.read() return -1 and we subsequently try to write 4 gigabytes to flash. Fixed by signed comparison and retry.

Author: Leif

libraries/ArduinoOTA/src/ArduinoOTA.cpp

@@ -315,6 +315,10 @@ void ArduinoOTAClass::_runUpdate() {
         size_t r = client.read(buf, available);
         if(r != available){
             log_w("didn't read enough! %u != %u", r, available);
+			if((int32_t) r<0){
+				delay(50);
+				continue;  	//let's not try to write 4 gigabytes when client.read returns -1
+			}
         }
 
         written = Update.write(buf, r);