I am trying to program the certificates on the nRF9151 Feather using Nordic Certificate Manager but it is failing with the error Unable to Write TLS credential

I am running the AT Client sample and I have put the nRF9151 Feather in offline mode using AT+CFUN=4

I have tried to write the certificates using the both the Serial Terminal and ExtraPutty but it seems to get the line endings wrong and even though it says OK I can see the hashes when looking at the results of AT%CMNG=1 are incorrect and the device does not connect to the Azure IoT Hub

I have seen the instructions for the nRF9160 Feather to use the old LTE Link Monitor/Certificate manager so I can see it was working for that device

I have found updating the certificates did not work using the 2.0.2 modem firmware and I had to downgrade to 2.0.0 to get these commands to work. The commands were failing with CME ERROR 527 on 2.0.2 modem firmware e.g.

AT%CMNG=0,77,1,"—–BEGIN CERTIFICATE—–
………………….
—–END CERTIFICATE—–"

6 days later

I found a workaround for this by changing the line endings in Notepad++ from the default of Windows (CRLF) to Unix (LF).

To do this in Notepad++ select the text and then go to Edit -> EOL Conversion -> Unix (LF). Then paste the AT commands from Notepad++ into ExtraPutty and the hash values will be then correct when you run AT%CMNG=1

For example

AT%CMNG=0,77,2,"—–BEGIN PRIVATE KEY—–[LF]
ABCD[LF]
EFGH[LF]
LMNO[LF]
—–END PRIVATE KEY—–"

instead of

AT%CMNG=0,77,2,"—–BEGIN PRIVATE KEY—–[CRLF]
ABCD[CRLF]
EFGH[CRLF]
LMNO[CRLF]
—–END PRIVATE KEY—–"

Sorry for the late response @jcd. This has been a pain for me too. Glad you got it figured out.

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