https://devzone.nordicsemi.com/f/nordic-q-a/22810/please-help-me-decide-this-addressHello, I&#39;m migrating a project from nrf51 to nrf52, and there is this function: uint32_t dfu_init(void) { m_cmd_handler = *((bl_if_cmd_handler_t*) (0x20000000 + ((uint32_t) (NRF_FICR-&gt;SIZERAMBLOCKS * NRF_FICR-&gt;NUMRAMBLOCK) - 4))); (uint32_t)en-USTelligent Community 13Fri, 16 Jun 2017 06:27:53 GMThttps://devzone.nordicsemi.com/thread/89689?ContentTypeID=1Fri, 16 Jun 2017 06:27:53 GMT137ad170-7792-4731-bb38-c0d22fbe4515:b252118c-4859-405e-bcbe-bbb50a1393e2Mitch996<p>To be perfectly honest I have no idea what this command handle is, I&#39;m yet to look into it, it wasn&#39;t originally written by me. And now that I know &gt;0x20000000 address = ram, this line of code does appear to be very odd, I&#39;ll get back later.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/89690?ContentTypeID=1Thu, 15 Jun 2017 11:01:02 GMT137ad170-7792-4731-bb38-c0d22fbe4515:d3c4af07-ce9f-4ae7-9d34-745defbf219ebjorn-spockeli<p>Hi Mitch, the RAM is memory-mapped from 0x20000000 on both the nRF51 and nRF52 Series, so that is correct. The total amount of RAM of the nRF52840 is stored in the INFO.RAM registers, so you can check it to verify that the RAM size is correct. What exactly is this command handler? If I have understood your implementation correct, then you&#39;ve placed the flash location of this command handler in RAM?</p><div style="clear:both;"></div>