z_arm_secure_fault on nRF9160 using flash_read after upgrade

Question

We appear to be getting a "z_arm_secure_fault" after the call to "flash_read", trying to access what appears to be any area of flash memory using tag v1.3.0. This call, including accompanying functions for erase and write, were working perfectly on tag v1.0.0 within addresses 0x040000-0x0FFFFF to store sensor readings. We haven't been able to locate any sort of read protection enable flag/option. It seems like this could be a simple issue, but we're not sure where to look. Any ideas? 
 These are the related options in "prj.conf", which have not changed among the two tag versions: 
 CONFIG_FLASH=y CONFIG_FLASH_PAGE_LAYOUT=y CONFIG_MPU_ALLOW_FLASH_WRITE=y CONFIG_SOC_FLASH_NRF=y 
 Thanks!

Arthur · Answer

We were able to solve the problem, at least tentatively, with the following call: 
 flash=device_get_binding("NRF_FLASH_DRV_NAME"); 
 To make things consistent, this can now be used for GPIO0 in NCS version 1.3.0: 
 p0=device_get_binding("GPIO_0"); 
 As an aside, the call to get a socket for AT commands is now this, which was difficult to find: 
 at_sock=socket(NRF_AF_LTE, SOCK_DGRAM, NPROTO_AT);