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Secure Boot Check Fail, Was Working Before

http://esp32.io/viewtopic.php?f=13&t=23338

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Secure Boot Check Fail, Was Working Before

Posted: Fri Sep 17, 2021 12:59 pm
by ConorShore
Hi,

The secure boot check is fail with no reason I can think of. Tried 3 boards and all end up in the same state. I've had this working before with no issue, so can't work out what i'm doing wrong now

Environment: DevKitC (ESP32-WROOM-32E), Modified version of ESP-AT firmware (based on V2.2.0.0), idf V4.2. Secure boot only (no encryption). Connected via the built in usb-uart chip

The fuses have already been programmed with generated command from build (see bottom for fuse table, and for generated commands), and the private key has never changed.

Steps:
1. erase_flash with esptool.py.
2. Build project with sdkconfig attached
3. Flash bootlooader with digest to 0x0. Terminal output:

Code: Select all

rst:0x3 (SW_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0040,len:100
load:0x3fff00a4,len:3764
load:0x40078000,len:28252
load:0x40080400,len:6328
Secure boot check failýets Jul 29 2019 12:21:46
4. Flash the rest with idf.py -p COM11 flash. Terminal output same as before.

What I don't understand is which part is failing. Is it the bootloader's signature, or the app's signature.

Any help would be greatly appreciated.

Many Thanks,
Conor

Generated bootloader commands:

Code: Select all

==============================================================================
Bootloader built and secure digest generated.
Secure boot enabled, so bootloader not flashed automatically.
Burn secure boot key to efuse using:
        C:\Users\cs\.espressif\python_env\idf0.3_py3.8_env\Scripts\python.exe C:/Users/cs/repo/esp-at-tester/WiFi_Firmware/esp-idf/components/esptool_py/esptool/espefuse.py burn_key secure_boot_v1 C:/Users/cs/repo/esp-at-tester/WiFi_Firmware/build/bootloader/secure-bootloader-key-256.bin
First time flash command is:
        C:\Users\cs\.espressif\python_env\idf0.3_py3.8_env\Scripts\python.exe C:/Users/cs/repo/esp-at-tester/WiFi_Firmware/esp-idf/components/esptool_py/esptool/esptool.py --chip esp32 --port=(PORT) --baud=(BAUD) --before=default_reset --after=no_reset write_flash --flash_mode dio --flash_freq 40m --flash_size 4MB 0x1000 C:/Users/cs/repo/esp-at-tester/WiFi_Firmware/build/bootloader/bootloader.bin
==============================================================================
To reflash the bootloader after initial flash:
        C:\Users\cs\.espressif\python_env\idf0.3_py3.8_env\Scripts\python.exe C:/Users/cs/repo/esp-at-tester/WiFi_Firmware/esp-idf/components/esptool_py/esptool/esptool.py --chip esp32 --port=(PORT) --baud=(BAUD) --before=default_reset --after=no_reset write_flash --flash_mode dio --flash_freq 40m --flash_size 4MB 0x0 C:/Users/cs/repo/esp-at-tester/WiFi_Firmware/build/bootloader/bootloader-reflash-digest.bin
==============================================================================
Partition table

Code: Select all

*******************************************************************************
# ESP-IDF Partition Table
# Name, Type, SubType, Offset, Size, Flags
phy_init,data,phy,0xe000,1K,
otadata,data,ota,0x10000,8K,
nvs,data,nvs,0x12000,56K,
at_customize,64,0,0x20000,896K,
ota_0,app,ota_0,0x100000,1536K,
ota_1,app,ota_1,0x280000,1536K,
*******************************************************************************

Code: Select all

Fuse table: 
Detecting chip type... ESP32
espefuse.py v3.0
EFUSE_NAME (Block)                       Description  = [Meaningful Value] [Readable/Writeable] (Hex Value)
----------------------------------------------------------------------------------------
Calibration fuses:
BLK3_PART_RESERVE (BLOCK0):              BLOCK3 partially served for ADC calibration data   = False R/W (0b0)
ADC_VREF (BLOCK0):                       Voltage reference calibration                      = 1114 R/W (0b00010)

Config fuses:
XPD_SDIO_FORCE (BLOCK0):                 Ignore MTDI pin (GPIO12) for VDD_SDIO on reset     = False R/W (0b0)
XPD_SDIO_REG (BLOCK0):                   If XPD_SDIO_FORCE, enable VDD_SDIO reg on reset    = False R/W (0b0)
XPD_SDIO_TIEH (BLOCK0):                  If XPD_SDIO_FORCE & XPD_SDIO_REG                   = 1.8V R/W (0b0)
CLK8M_FREQ (BLOCK0):                     8MHz clock freq override                           = 50 R/W (0x32)
SPI_PAD_CONFIG_CLK (BLOCK0):             Override SD_CLK pad (GPIO6/SPICLK)                 = 0 R/W (0b00000)
SPI_PAD_CONFIG_Q (BLOCK0):               Override SD_DATA_0 pad (GPIO7/SPIQ)                = 0 R/W (0b00000)
SPI_PAD_CONFIG_D (BLOCK0):               Override SD_DATA_1 pad (GPIO8/SPID)                = 0 R/W (0b00000)
SPI_PAD_CONFIG_HD (BLOCK0):              Override SD_DATA_2 pad (GPIO9/SPIHD)               = 0 R/W (0b00000)
SPI_PAD_CONFIG_CS0 (BLOCK0):             Override SD_CMD pad (GPIO11/SPICS0)                = 0 R/W (0b00000)
DISABLE_SDIO_HOST (BLOCK0):              Disable SDIO host                                  = False R/W (0b0)

Efuse fuses:
WR_DIS (BLOCK0):                         Efuse write disable mask                           = 256 R/W (0x0100)
RD_DIS (BLOCK0):                         Efuse read disable mask                            = 2 R/W (0x2)
CODING_SCHEME (BLOCK0):                  Efuse variable block length scheme
   = NONE (BLK1-3 len=256 bits) R/W (0b00)
KEY_STATUS (BLOCK0):                     Usage of efuse block 3 (reserved)                  = False R/W (0b0)

Identity fuses:
MAC (BLOCK0):                            Factory MAC Address
   = 44:17:93:5e:41:40 (CRC 0x7b OK) R/W
MAC_CRC (BLOCK0):                        CRC8 for factory MAC address                       = 123 R/W (0x7b)
CHIP_VER_REV1 (BLOCK0):                  Silicon Revision 1                                 = True R/W (0b1)
CHIP_VER_REV2 (BLOCK0):                  Silicon Revision 2                                 = True R/W (0b1)
CHIP_VERSION (BLOCK0):                   Reserved for future chip versions                  = 2 R/W (0b10)
CHIP_PACKAGE (BLOCK0):                   Chip package identifier                            = 1 R/W (0b001)
MAC_VERSION (BLOCK3):                    Version of the MAC field                           = 0 R/W (0x00)

Security fuses:
FLASH_CRYPT_CNT (BLOCK0):                Flash encryption mode counter                      = 0 R/W (0b0000000)
UART_DOWNLOAD_DIS (BLOCK0):              Disable UART download mode (ESP32 rev3 only)       = False R/W (0b0)
FLASH_CRYPT_CONFIG (BLOCK0):             Flash encryption config (key tweak bits)           = 0 R/W (0x0)
CONSOLE_DEBUG_DISABLE (BLOCK0):          Disable ROM BASIC interpreter fallback             = True R/W (0b1)
ABS_DONE_0 (BLOCK0):                     Secure boot V1 is enabled for bootloader image     = True R/W (0b1)
ABS_DONE_1 (BLOCK0):                     Secure boot V2 is enabled for bootloader image     = False R/W (0b0)
JTAG_DISABLE (BLOCK0):                   Disable JTAG                                       = False R/W (0b0)
DISABLE_DL_ENCRYPT (BLOCK0):             Disable flash encryption in UART bootloader        = False R/W (0b0)
DISABLE_DL_DECRYPT (BLOCK0):             Disable flash decryption in UART bootloader        = False R/W (0b0)
DISABLE_DL_CACHE (BLOCK0):               Disable flash cache in UART bootloader             = False R/W (0b0)
BLOCK1 (BLOCK1):                         Flash encryption key
   = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W
BLOCK2 (BLOCK2):                         Secure boot key
   = ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? -/-
BLOCK3 (BLOCK3):                         Variable Block 3
   = 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 R/W

Flash voltage (VDD_SDIO) determined by GPIO12 on reset (High for 1.8V, Low/NC for 3.3V).

Re: Secure Boot Check Fail, Was Working Before

Posted: Tue Sep 21, 2021 8:21 am
by ConorShore
Can anyone help?

Re: Secure Boot Check Fail, Was Working Before

Posted: Tue Sep 21, 2021 6:41 pm
by WiFive
viewtopic.php?t=7133

Re: Secure Boot Check Fail, Was Working Before

Posted: Wed Sep 22, 2021 7:09 am
by ESP_Mahavir
What I don't understand is which part is failing. Is it the bootloader's signature, or the app's signature.
Log indicates that ROM loader has failed to verify signature for 2nd stage bootloader. So this error is about incorrect bootloader signature.

Few things that may help here:

1. Please check on bootloader size and partition table offset overlap per note at https://docs.espressif.com/projects/esp ... oader-size
2. Please re-confirm if bootloader is indeed getting signed using correct key per already programmed in device eFuse

Re: Secure Boot Check Fail, Was Working Before

Posted: Wed Sep 22, 2021 9:32 am
by ConorShore
Thanks for the reply,

1. bootloader with digest is 45056 bytes (0xb000 bytes) + 0x1000 = 0xc000. My partition offset is set to 0xd000, so that shouldn't be a problem right?
2. I haven't changed the key used to create the digest ever, and i can confirm its in re-flashable mode. Is there any futher action you suggest to verify? I'm using the esp-at's build script for all of this.

Re: Secure Boot Check Fail, Was Working Before

Posted: Wed Sep 22, 2021 11:48 am
by ESP_Mahavir
1. bootloader with digest is 45056 bytes (0xb000 bytes) + 0x1000 = 0xc000. My partition offset is set to 0xd000, so that shouldn't be a problem right?
Yes. Partition table offset looks good, no overlapping with bootloader here.

I am not much familiar with "esp-at" build script but overall secure-boot build workflow is quite straight-forward. Please refer to documentation at https://docs.espressif.com/projects/esp ... ot-v1.html.

As long as secure boot key remains same per section at https://docs.espressif.com/projects/esp ... bootloader, I do not see any problem in verification of bootloader part. Can you please confirm that you had not made any modification to build system and carrying forward same "secure boot" key in all your attempts?

Re: Secure Boot Check Fail, Was Working Before

Posted: Wed Oct 20, 2021 6:13 am
by callux
Have a look in the menuconfig and check in the Security section if the Secure Bootloader settings are properly ticked.
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