Adding CONFIG_SECURE_BOOT locks NRF5340

[dev_j]

Hello,

While working with a custom board with nrf5340 and instead of DCDC inductors, has voltage regulators. Why does CONFIG_SECURE_BOOT lock up the custom board but not the Nordic devkit?
Same output like this post, but seems like the solution was not posted: https://devzone.nordicsemi.com/f/nordic-q-a/95935/added-an-immutable-bootloader-and-can-no-longer-connect-to-adafruit-feather-express-nrf52840-in-nrf-connect-or-programmer-v3-04

Thanks

[Kenneth]

Hello,

In the board files make sure to use regulator-initial-mode = <NRF5X_REG_MODE_LDO>;

Kenneth

[dev_j]

Hi Kenneth Thank you for your response.  We are using an older NCS v2.6.0, because of that we are setting the following parameters

CONFIG_BOARD_ENABLE_DCDC_APP=n

CONFIG_BOARD_ENABLE_DCDC_NET=n

CONFIG_BOARD_ENABLE_DCDC_HV=n

in our prj.conf (we are also setting them in our child image).  The custom board does not lock up when we have CONFIG_SECURE_BOOT disabled.  When we set CONFIG_SECURE_BOOT=y our custom board locks up.

is setting regulator-initial-mode = <NRF5X_REG_MODE_LDO>; the same as setting the above parameters?

[Kenneth]

I suspect the bootloader here still try to use the DCDC, so  best to use the devicetree overlay yes (or you need to add the config option to the bootloader image also).

Kenneth

[dev_j]

Hi Kenneth 
We are already setting the

CONFIG_BOARD_ENABLE_DCDC_APP=n

CONFIG_BOARD_ENABLE_DCDC_NET=n

CONFIG_BOARD_ENABLE_DCDC_HV=n

parameters in our mcuboot.conf under child_image; that made it so we were able to get it to work without CONFIG_SECURE_BOOT=y in the prj.conf; when we set CONFIG_SECURE_BOOT=y is when our board is locking up.

[Kenneth]

Can you search through your build folder for all zephyr.dts and .config files? And share them here?

Kenneth