Programming nRF51 bootloader with nrfjprog.exe 7.5.1

Question

Hi 
 I've installed the new tools in version 7.5.1 to support the new nRF52 family. While working on the nRF51 again i found out, that the old parameters i used for programming my bootloader are not working anymore.
Old call: nrfjprog.exe --reset --program "bootloader.HEX" 
 This call programmed my bootloader at address 0x3C000 and programmed the bootloader address in the UICR page (if not already done). 
 I adapted my call to work with the new tool and ended in the following call:
nrfjprog.exe --family NRF51 --program "bootloader.HEX" 
 The problem is, that it only works if the UICR bootloader address is not yet written. If the same value already is programmed an error occurs. 
 How can we reach the same behaviour with the new nrfjprog? 
 Regards Adrian

Susheel Nuguru · Accepted Answer

normally this should work 
 nrfjprog.exe --eraseuicr
nrfjprog.exe --erasepage 0X3C000-0X40000
nrfjprog.exe --reset --program "bootloader.HEX"
 
 But i have problem with --eraseuicr not working for pca100028 with
nrfjprog version: 7.5.1
JLinkARM.dll version: 4.98c 
 EDIT: 
 --eraseuicr is not available on nRF51 chips if it is not pre programmed with software at the production time.
So you probably have to erase full chip if you want to write your bootloader file. 
 nrfjprog.exe --eraseall
nrfjprog.exe --reset --program "bootloader.HEX"