Is there a way to downgrade firmware for nRF9160 modem?

[zz1956t]

Hi, 

Recently I obtained an old development kit of nRF9160 (Board:PCA10090 0.8.5 2019.7, nRF9160:BAA-E2.1.8 12149). When starting to use it,
I followed the instructions in Quick Start v0.2.0 for nRF Connect for Desktop v4.3.0 and the modem firmware version is now v1.3.5.

An error was displayed on Verify, so I checked the firmware download page and found the following statement, so I would like to downgrade the firmware on my nRF9160 modem.
However, unfortunately, when I read a previous article, it was written that the modem firmware cannot be downgraded. Is there a way to downgrade the modem firmware on an older nRF9160 to version 1.2.8 or lower?

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Before applying this version:

Note that this modem firmware is targeted nRF9160 SiP Revision 2
It can be used for nRF9160 SiP Revision 1, but only for testing and development
It cannot be used for engineering samples of Revision 1 (e.g. DKs or Thingy:91 with version older than v0.9.0)
After you upgrade to MFW 1.3.x it is not recommended to downgrade to MFW 1.2.x or MFW 1.1.x.(potential file system issues)
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Thanks & Best regards,

zz1956t

[Øyvind]

Hello, 

Due to Christmas holiday in our technical support team we are lower staffed than normal, this may cause some delays in our answers. Sorry for the inconvenience. 

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The development kit you are using is fairly old, an engineering version of the nRF9160, and we recommend getting a newer version. 

Kind regards,
Øyvind

[zz1956t]

It doesn't matter if the functionality is old, but is there a way to downgrade the modem's firmware to make it usable?

[Øyvind]

You can program modem FW 1.2.8 to test. Just open the programmer app in nRF Connect for Desktop and pull the modem zip file in. I did test on my side without issues, however, I had to use a fairly old version of our SDK for it to work.

[zz1956t]

Hi, Øyvind-san

Arigato (Thank you for your reply.)

I tried immediately.
When I tried reading nfw_nrf9160_1.2.8.zip after writing it, it looked like the attached file.
The modem firmware does not seem to be displayed on this screen, is this correct?

Also, please let me know the version of the SDK that has been confirmed to work.

Thanks & Best regards,

zz1956t

[Øyvind]

zz1956t said:

The modem firmware does not seem to be displayed on this screen, is this correct?

No other indication other than the .zip file name in the left "window". If you click on write from the left hand side it should program the device. 

[zz1956t]

The attached file was read after clicking write.

Is there a way to check that the modem firmware was written correctly?

[zz1956t]

I confirmed that it works with at_client sample included in SDK v1.5.1, nfw_nrf9160_1.2.8.zip and nrf9160_dk_board_controller_fw_2.0.1.hex.

thank you very much.