Error reading UICR-OTP registers in SDK 1.9.1 (result is 0xdeaddead)

Question

Hello, I have been using the SPM to read the UICR->OTP[0] register in SDK1.2.1, 1.4.2, and 1.5.1 but it's not able to when I'm using version 1.9.1. 
 I have patched the \1.9.1
rf\subsys\spm\secure_services.c with: 
 {.start = NRF_UICR_S_BASE, .size = sizeof(NRF_UICR_Type)}, 
 Using this function: spm_request_read(&result, 0x00FF8108, 4); 
 I see when using a debuger that it copies the content of 0x00f f8108, but the result is not 0x00000002 but 0xdeaddead. 
 What is locking the access, and how to unlock it? 
 I use this command to program the value from Windows command prompt: nrfjprog --memwr 0x00FF8108 --val 2 -f nrf91 
 I verify that the value is correct with this command: nrfjprog --memrd 0x00FF8108 -f nrf91

Håkon Alseth · Accepted Answer

Hi, 
 
 Thank you very much for your patience in this matter. 
 The issue that happens when the read to the UICR section is added: 
 {.start = NRF_UICR_S_BASE, .size = sizeof(NRF_UICR_Type)}, 
 Is that the memcpy() further along in the secure_services.c::spm_request_read_nse() does not take into account nRF9160 erratum #7: 
 https://infocenter.nordicsemi.com/topic/errata_nRF9160_Rev2/ERR/nRF9160/Rev2/latest/anomaly_160_7.html?cp=2_0_1_0_1_4 
 
 Here is a proposed workaround (which can be inserted here https://github.com/nrfconnect/sdk-nrf/blob/v1.9.1/subsys/spm/secure_services.c#L105 ) : 
 /* UICR needs special handling due to nRF9160 erratum #7 */
/* Please change the range as fits your requirements */
if (addr >= NRF_UICR_S_BASE && addr <= (NRF_UICR_S_BASE+offsetof(NRF_UICR_Type, OTP[20]))) {
	uint32_t * tmp_dest = (uint32_t *)destination;
	volatile uint32_t * tmp_addr = (volatile uint32_t *)addr;
	for (int i = 0; i < (len / sizeof(uint32_t)); i++) { 
 volatile uint32_t tmp_uicr = tmp_addr[i];
 __DSB(); 
 tmp_dest[i] = tmp_uicr;
	}
	return 0;
} 
 
 Could you try this and report back? 
 
 Kind regards, 
 Håkon

Error reading UICR->OTP registers in SDK 1.9.1 (result is 0xdeaddead)

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