https://devzone.nordicsemi.com/f/nordic-q-a/16856/retaining-a-few-bytes-in-the-nrf51-after-a-restart-from-system_offI&#39;d like to retain a few bytes after a restart from system_off. I know the GPIO state is retained, are there any other registers other than that? It looks like RTC1-&gt;CC[0] is, but oddly enough CC[1] isn&#39;t (or is getting clobbered). I&#39;m using the softdeven-USTelligent Community 13Tue, 04 Oct 2016 23:45:54 GMThttps://devzone.nordicsemi.com/thread/64542?ContentTypeID=1Tue, 04 Oct 2016 23:45:54 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b38b0d1a-06e1-4856-9d84-70ed5140361fRK<p>You&#39;re just getting lucky. On the nRF51 the only registers retained after a start from system off are listed in the manual, and the only one you can really use is GPREGRET, which gives you 32 bits. If you need more than that then you really have to store your data in flash.</p><div style="clear:both;"></div>