A UICR write operation has been requested but UICR has not been erased

Question

There are already a few threads about this problem but none of them helped. 
 I want to use GPIO9 + 10 as .. well .. GPIO. 
 Here's what I did: 
 
 added CFLAGS += -DCONFIG_NFCT_PINS_AS_GPIOS in Makefile 
 added a section in linker script: 
 
 
 UICR_NFCPINS(r) : ORIGIN = 0x1000120C, LENGTH = 0x04 
 
 
 SECTIONS {
/* Write the bootloader address in UICR. /
.uicrNfcPinsAddress :
{
KEEP( (.uicrNfcPinsAddress))
} > UICR_NFCPINS
} 
 
 
 set the constant in main.c: const uint32_t UICR_ADDR_0x20C attribute ((section(".uicrNfcPinsAddress"))) attribute ((used)) = 0xFFFFFFFE; 
 
 And after all, still it didn't help, I always had the "A UICR write operation..." message and the GPIOs didn't work. 
 Finally I did nrfjprog --memwr 0x1000120c --val 0xFFFFFFFE --family nrf52 --verify 
That helped but is not best practice, I guess - and still the message did not disappear (but the GPIOs work at least) 
 Any help please?