Downgrade protection works only for the app_core -image-and not for the net-core -image

[Georg]

Hallo,

we are using the nrf5340 and the ncs Version 2.6.1.

I activated the software downgrade protection as described here Downgrade protection (nordicsemi.com). 

Then I made some simultaneious FOTA updates (App-image + Net-image) by using the nRF Connect app with different versions.

What I see is that the downngrade protection works for the App-image. It is not possible to update an App-image V2.0.0. with an App-image V1.0.0.

But it is possible to downgrade the Net- image V2.0.0 with the Net-image V1.0.0

How can I activate the downgrade protection also for the net-core ?

 

Best regards,

Georg

[Amanda Hsieh]

Hi, 

Do you test the MCUBoot version by adjusting CONFIG_MCUBOOT_HW_DOWNGRADE_PREVENTION_COUNTER_VALUE?

How do you check the version number? You can check the version by 

imgtool verify build/zephyr/net_core_app_update.bin

Regards,
Amanda H.

[Georg]

Hi,

I checked the version information by looking into the header of the net_core_app update.bin file.  

Here are the configuration switches which I have added to activate the downgrade prevention:

CONFIG_BOOT_VERSION_CMP_USE_BUILD_NUMBER=y
CONFIG_MCUBOOT_DOWNGRADE_PREVENTION=y

In the build configuration I added:

-DSB_CONFIG_MCUBOOT_MODE_OVERWRITE_ONLY=y

And  there is also a VERSION file which looks like this:

Some additional information:

We are using a serial external flash to store the secondary images of the app-core and the net-core.

After making an simultaineious update by using dfu_application.zip it seems that the header ifnormation of the net_core_app_update.bin is corrupt when lokking into the memory of the nrf5340-net-core. So there is no version information any more.

When looking into the memory of the app-core the header information seems to be ok 

Best regards,

Georg

[Georg]

Hi Amanda,

thank you for your answer and sorry for my late reply.

Up to now I didn't a have file b0n.conf . So I created this file with only this entry. 

CONFIG_PCD_READ_NETCORE_APP_VERSION=y

I tried your solution but get some errors during build.

-- west build: generating a build system
Loading Zephyr default modules (Zephyr base).
-- Application: C:/Projekte/BleCan_CAB11A
-- CMake version: 3.21.0
-- Found Python3: C:/ncs/toolchains/cf2149caf2/opt/bin/python.exe (found suitable version "3.9.13", minimum required is "3.8") found components: Interpreter
-- Cache files will be written to: C:/DevTools/ncs/v2.6.1/zephyr/.cache
-- Zephyr version: 3.5.99 (C:/DevTools/ncs/v2.6.1/zephyr)
CMake Error at C:/DevTools/ncs/v2.6.1/zephyr/cmake/modules/version.cmake:76 (math):
math cannot parse the expression: "(2 << 16) + ( << 8) + (0)": syntax
error, unexpected exp_SHIFTLEFT (16).
Call Stack (most recent call first):
C:/DevTools/ncs/v2.6.1/zephyr/cmake/modules/zephyr_default.cmake:129 (include)
C:/DevTools/ncs/v2.6.1/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
C:/DevTools/ncs/v2.6.1/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:92 (include_boilerplate)
CMakeLists.txt:14 (find_package)

CMake Error at C:/DevTools/ncs/v2.6.1/zephyr/cmake/modules/version.cmake:77 (math):
math cannot parse the expression: "(2 << 24) + ( << 16) + (0 << 8) +
(2408081002)": syntax error, unexpected exp_SHIFTLEFT (16).
Call Stack (most recent call first):
C:/DevTools/ncs/v2.6.1/zephyr/cmake/modules/zephyr_default.cmake:129 (include)
C:/DevTools/ncs/v2.6.1/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:66 (include)
C:/DevTools/ncs/v2.6.1/zephyr/share/zephyr-package/cmake/ZephyrConfig.cmake:92 (include_boilerplate)
CMakeLists.txt:14 (find_package)

Best regards,

Georg

[Georg]

• Hi,

  the problem with the error is solved.

  After flashing the software with the additional config switches, our software doesn't boot any more

  It seems that the software hangs in the bootoloader.

   

  Rest regards,

  Georg

[Georg]

Hi, 

the program hangs  in the "do while" loop  of the function: network_core_pcd_cmdset in the file pcd.c

The command_status is PCD_STATUS_READ_VERSION

tatic int network_core_pcd_cmdset(uint32_t cmd, const void *src_addr, size_t len, bool wait)
{
	int err;
	enum pcd_status command_status;

	/* Ensure that the network core is turned off */
	nrf_reset_network_force_off(NRF_RESET, true);

	err = pcd_cmd_write(cmd, src_addr, len, PCD_NET_CORE_APP_OFFSET);
	if (err != 0) {
		LOG_INF("Error while writing PCD cmd: %d", err);
		return err;
	}

	enum pcd_status initial_command_status = pcd_fw_copy_status_get();

	nrf_reset_network_force_off(NRF_RESET, false);
	LOG_INF("Turned on network core");

	if (!wait) {
		return 0;
	}

	do {
		/* Wait for 1 second to avoid issue where network core
		 * is unable to write to shared RAM.
		 */
		k_busy_wait(1 * USEC_PER_SEC);

		command_status = pcd_fw_copy_status_get();
	} while (command_status == initial_command_status);

Best regards,

Georg

[Amanda Hsieh]

Did you add CONFIG_PCD_READ_NETCORE_APP_VERSION for b0n? This option must be enabled in APP, MCUboot, and b0n configuration (when b0n is not configured, than application hangs after reboot).

[Georg]

Hi,

this is what I added to the config files to activate the downgrade protection in complete.

mcuboot.conf under child_image folder:

CONFIG_BOOT_VERSION_CMP_USE_BUILD_NUMBER=y

CONFIG_MCUBOOT_DOWNGRADE_PREVENTION=y

CONFIG_FW_INFO=y
CONFIG_PCD_APP=y
CONFIG_PCD_READ_NETCORE_APP_VERSION=y

hci_ipc.conf under child_image folder:

CONFIG_FW_INFO_FIRMWARE_VERSION=2

b0n.conf under child_image folder:

CONFIG_PCD_READ_NETCORE_APP_VERSION=y

prj.conf:

CONFIG_FW_INFO=y
CONFIG_PCD_APP=y
CONFIG_PCD_READ_NETCORE_APP_VERSION=y

Since my last mail, I added only the 3 config switches in the prj.conf file.

The application doesn't boot and the mcuboot hangs in the loop as described above.

Best regards,

Georg

[Amanda Hsieh]

Sounds it works as expected now with your configs files. Right?

[Georg]

Hi,

no, it doesn't work. The system doesn't boot and hangs still in the "do while" of the mcuboot.

[Georg]

Hi,

are there some new ideas concerning this problem ?

Best regards, 

Georg

[Amanda Hsieh]

Add CONFIG_PCD_READ_NETCORE_APP_VERSION=y to nrf\samples\nrf5340\netboot\prj.conf and check whether `CONFIG_PCD_READ_NETCORE_APP_VERSION is set in hci_ipc/b0n/zephyr/.config

[Georg]

Hi, 

there is no subdirectory "/b0n/zephyr" under the directory "/ncs/v2.6.1/zephyr/samples/bluetooth/hci_ipc" in the ncs sdk 2.6.1.

Best regards

Georg