https://devzone.nordicsemi.com/f/nordic-q-a/4821/bug-report-non-blocking-operation-in-retarget-cI&#39;m developing an UART with SD110. I&#39;ve updated the SDK to the newest 7.1 and I&#39;m using MDK Pack-Installer. I found a problem in app_uart.c and retarget.c . retarget.c retargets printf , which calls fputc to send a single char. int fputc(inten-USTelligent Community 13Wed, 06 May 2015 10:01:46 GMThttps://devzone.nordicsemi.com/thread/17060?ContentTypeID=1Wed, 06 May 2015 10:01:46 GMT137ad170-7792-4731-bb38-c0d22fbe4515:da52e66c-04ff-4859-8ff3-717f873d1c79jithin m das<p>I had done this. But the problem is it some times get hang because app_uart_put() will not be returning from the NRF_SUCCESS if UART gets stuck. So the whole program gets stuck and nothing will be working.</p><div style="clear:both;"></div>