https://devzone.nordicsemi.com/f/nordic-q-a/13819/migrating-from-nrf51422-to-nrf51822-gets-an-errorI am using uVision 5.18a with MDK-Lite ARM toolchain and I downloaded nRF examples for SDK 11.0.0-2.alpha with Pack Installer. Then I tried to compile &quot; /ble_peripheral/ble_app_uart &quot; with S130 Softdevice and everything goes OK if I use nRF51 4 22_xxACen-USTelligent Community 13Wed, 18 May 2016 11:06:38 GMThttps://devzone.nordicsemi.com/thread/52816?ContentTypeID=1Wed, 18 May 2016 11:06:38 GMT137ad170-7792-4731-bb38-c0d22fbe4515:74737c85-3745-402b-b095-3d0c659b2d67Susheel Nuguru<p>There is nrf_drv_config.h in the SDK folder, but if you are using packs then it is using config from</p> <blockquote> <p>C:\Keil_v5\ARM\Pack\NordicSemiconductor\nRF_Drivers\4.0.0-2.alpha\config</p> </blockquote> <p>Make sure that all the flags needed are update in this path.</p><div style="clear:both;"></div>https://devzone.nordicsemi.com/thread/52815?ContentTypeID=1Wed, 18 May 2016 00:38:08 GMT137ad170-7792-4731-bb38-c0d22fbe4515:86a0a5ed-cd09-416a-93b5-6f81d5bdfd69zhwzh308<p>There could be different issues causing this:</p> <ul> <li>RAM size is different between the two, so you will need to set linker script to appropriate value;</li> <li>SDK is alpha, maybe you should switch to production SDK 11;</li> <li>Defines are different, after switching to nRF51822 you may have to update nrf_drv_config.h in pca10031 folder (not sure on this one)</li> </ul><div style="clear:both;"></div>