MCU-PLUS-SDK-AM243X: debug SBL signing failure for LP-AM263

Andy MacGregor

Part Number: MCU-PLUS-SDK-AM243X
Other Parts Discussed in Thread: UNIFLASH

I'm trying to build the QSPI SBL example for the AM263x LaunchPad from source unsuccessfully.

I think something is wrong with the resulting binary, because I load it to flash with uniflash, then set the boot mode pins to UART boot mode (like below), then reset the board, and I see XMODEM output as if the board dip switches were set to UART boot mode. I realize this boot pin configuration sets the RBL fallback mode to UART, so I think that means that QSPI RBL is failing.

Both the sbl_qspi.debug.tiimage and sbl_qspi.release.tiimage prebuilt SBLs packaged at tools/boot/sbl_prebuilt/am263x-lp work, so I think my individual board isn't causing this problem.

I'm using MCU+SDK 08_06_00_34, and I imported the SBL QSPI example into CCS from this MCU+SDK directory: examples/drivers/boot/sbl_qspi/am263x-lp/r5fss0-0_nortos I built the SBL without changing anything after importing.

I've also tried adding the `loop_forever()` function to the top of main() in the example QSPI SBL source like suggested here, however CPU execution isn't in that loop when I connect the debugger, which supports my thought that QSPI RBL is failing. https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1119575/faq-mcu-plus-sdk-am243x-how-to-debug-sbl_qspi-for-am263-and-am273-or-sbl_ospi-for-am243-or-an-application-which-is-booted-via-ospi-qspi-boot

This is what my uniflash.cfg file looks like:

# First point to sbl_uart_uniflash binary, which function's as a server to flash one or more files
--flash-writer=/home/amacgregor/ti/mcu_plus_sdk_am263x_08_06_00_34/tools/boot/sbl_prebuilt/am263x-lp/sbl_uart_uniflash.release.tiimage
# When sending bootloader make sure to flash at offset 0x0. ROM expects bootloader at offset 0x0
--file=/opt/ti/ccs_2023_workspace_v12/sbl_qspi_am263x-lp_r5fss0-0_nortos_ti-arm-clang/Debug/sbl_qspi_am263x-lp_r5fss0-0_nortos_ti-arm-clang.tiimage --operation=flash --flash-offset=0x0

What steps can I take to debug this further and end up with a compiling QSPI SBL source code that I can customize?

Thank you,

-Andy

over 2 years ago

+1 Aakash Kedia over 2 years ago

TI__Mastermind 26145 points

Hi Andy MacGregor,

Andy MacGregor said:
What steps can I take to debug this further and end up with a compiling QSPI SBL source code that I can customize?

Can you confirm which openssl version is being used ?

Are you using the version mentioned here -

https://software-dl.ti.com/mcu-plus-sdk/esd/AM263X/latest/exports/docs/api_guide_am263x/SDK_DOWNLOAD_PAGE.html#INSTALL_OPENSSL

Can you try with this version of openssl ?

Hope it helps.

Best Regards,
Aakash

0 Andy MacGregor over 2 years ago in reply to Aakash Kedia

Intellectual 257 points

Thank you Aakash. I was running with OpenSSL 3.0.2; building the bootloader with OpenSSL 1.1.1 fixed the problem.

In case it helps anyone else, here is a patch for mcu+sdk08.06.00 that fails making the x509 image if the wrong openSSL version is detected.

diff --git a/tools/boot/signing/mcu_rom_image_gen.py b/tools/boot/signing/mcu_rom_image_gen.py
index f82a14e..73bd7f1 100644
--- a/tools/boot/signing/mcu_rom_image_gen.py
+++ b/tools/boot/signing/mcu_rom_image_gen.py
@@ -132,6 +132,12 @@ def get_cert(args):
                                 )
     return dedent(ret_cert)

+def check_openssl():
+    v = subprocess.check_output(['openssl', 'version']).decode()
+    if v.find('OpenSSL 1.1.1') < 0:
+        print("Requires OpenSSL v1.1.1")
+        exit(1)
+
 # MAIN
 my_parser = argparse.ArgumentParser(description="Creates a ROM-boot-able images for sbl and hsmRt")

@@ -144,6 +150,7 @@ my_parser.add_argument('--out-image',   type=str, required=True, help='Output fi
 my_parser.add_argument('--debug',       type=str, help='Debug options for the image')

 args = my_parser.parse_args()
+check_openssl()

 cert_str = get_cert(args)
 # print(cert_str)

0 Aakash Kedia over 2 years ago in reply to Andy MacGregor

TI__Mastermind 26145 points

Hi Andy

Thanks, We will integrate this check in the scripts.

Best Regards,
Aakash

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MCU-PLUS-SDK-AM243X: debug SBL signing failure for LP-AM263