burn_key operation gives Burn BLOCK_KEY0 (['BLOCK4']) was not successful (ESPTOOL-986)

[Daphne-HU]

Operating System

Xubuntu 20.04 (under WSL)

Esptool Version

4.7.0

Python Version

3.8.10

Chip Description

esp32-C3-mini-1

Device Description

Chip is on a custom PCB

Hardware Configuration

When relevant i can provide pin configurations

How is Esptool Run

Visual studio code

Full Esptool Command Line that Was Run

espefuse.py --debug burn_key BLOCK_KEY0 flash_encryption_key.bin XTS_AES_128_KEY

Esptool Output

vscode@4d6257b198cd:/workspaces/BCE-Monitor$ espefuse.py --debug burn_key BLOCK_KEY0 flash_encryption_key.bin XTS_AES_128_KEY
espefuse.py v4.7.0
Connecting...
Detecting chip type... ESP32-C3
BLOCK0          (                ) [0 ] read_regs: 00000000 00000000 00000000 00000000 80000000 00000000
MAC_SPI_8M_0    (BLOCK1          ) [1 ] read_regs: <data>
BLOCK_SYS_DATA  (BLOCK2          ) [2 ] read_regs: <data>
BLOCK_USR_DATA  (BLOCK3          ) [3 ] read_regs: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
BLOCK_KEY0      (BLOCK4          ) [4 ] read_regs: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
BLOCK_KEY1      (BLOCK5          ) [5 ] read_regs: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
BLOCK_KEY2      (BLOCK6          ) [6 ] read_regs: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
BLOCK_KEY3      (BLOCK7          ) [7 ] read_regs: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
BLOCK_KEY4      (BLOCK8          ) [8 ] read_regs: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
BLOCK_KEY5      (BLOCK9          ) [9 ] read_regs: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
BLOCK_SYS_DATA2 (BLOCK10         ) [10] read_regs: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

BLOCK0          (                ) [0 ] err__regs: 00000000 00000000 00000000 00000000 00000000 00000000
EFUSE_RD_RS_ERR0_REG        0x00000000
EFUSE_RD_RS_ERR1_REG        0x00000000

=== Run "burn_key" command ===
Burn keys to blocks:
 - BLOCK_KEY0 -> [<my key>]
        Reversing byte order for AES-XTS hardware peripheral
        'KEY_PURPOSE_0': 'USER' -> 'XTS_AES_128_KEY'.
        Disabling write to 'KEY_PURPOSE_0'.
        Disabling read to key block
        Disabling write to key block


Check all blocks for burn...
idx, BLOCK_NAME,          Conclusion
[00] BLOCK0               is not empty
        (written ): 0x000000008000000000000000000000000000000000000000
        (to write): 0x<key>
        (coding scheme = NONE)
[01] MAC_SPI_8M_0         nothing to burn
[02] BLOCK_SYS_DATA       nothing to burn
[03] BLOCK_USR_DATA       nothing to burn
[04] BLOCK_KEY0           is empty, will burn the new value
[05] BLOCK_KEY1           nothing to burn
[06] BLOCK_KEY2           nothing to burn
[07] BLOCK_KEY3           nothing to burn
[08] BLOCK_KEY4           nothing to burn
[09] BLOCK_KEY5           nothing to burn
[10] BLOCK_SYS_DATA2      nothing to burn
. 
This is an irreversible operation!
Type 'BURN' (all capitals) to continue.
BURN
BLOCK_KEY0      (BLOCK4          ) [4 ] to_write: <my key>
Write data to BLOCK4
Addr 0x60008800, data=0x..
Addr 0x60008804, data=0x..
Addr 0x60008808, data=0x..
Addr 0x6000880c, data=0x..
Addr 0x60008810, data=0x..
Addr 0x60008814, data=0x..
Addr 0x60008818, data=0x..
Addr 0x6000881c, data=0x..
Addr 0x60008820, data=0x..
Addr 0x60008824, data=0x..
Addr 0x60008828, data=0x..
BLOCK_KEY0      (BLOCK4          ) [4 ] read_regs: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
BLOCK_KEY0      (BLOCK4          ) [4 ] Expected: <my key>
BLOCK_KEY0      (BLOCK4          ) [4 ] Real    : 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000

A fatal error occurred: Burn BLOCK_KEY0 (['BLOCK4']) was not successful

More Information

I followed the documentation as noted here, under Using Host Generated Key:
https://docs.espressif.com/projects/esp-idf/en/release-v5.1/esp32c3/security/flash-encryption.html

When I run "espefuse.py summary," it displays what appears to be the basic fabric configuration settings.
Nothing is changed before trying to burn the flash key.

Other Steps to Reproduce

I Have Read the Troubleshooting Guide

• I confirm I have read the troubleshooting guide.

[KonstantinKondrashov]

Hi @Daphne-HU!
The command is correct. If nothing is changed then the problem is likely hardware-related. You can try programming it into a different BLOCK_KEY.
Possible hardware-related issues:

• ESD (Electrostatic Discharge): Ensure proper handling and grounding to prevent damage.
• Weak Power Supply: Verify the power supply's stability and ensure it meets the ESP32-C3's voltage and current requirements.

[Daphne-HU]

I have attempted the suggested solutions, including using different power supplies and PCBs, but the issue persists. I also tried programming a different BLOCK_KEY without success. Could there be other potential causes or solutions to this problem?

on a new device i tried writing with no read and write protect:

vscode@4d6257b198cd:/workspaces/BCE-Monitor$ espefuse.py burn_key --no-write-protect --no-read-protect BLOCK_KEY4 flash_encryption_key.bin XTS_AES_128_KEY
espefuse.py v4.7.0
Connecting...
Detecting chip type... ESP32-C3

=== Run "burn_key" command ===
Sensitive data will be hidden (see --show-sensitive-info)
Burn keys to blocks:

• BLOCK_KEY4 -> [?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ?? ??]
  Reversing byte order for AES-XTS hardware peripheral
  'KEY_PURPOSE_4': 'USER' -> 'XTS_AES_128_KEY'.
  Disabling write to 'KEY_PURPOSE_4'.

Keys will remain writeable (due to --no-write-protect)
Keys will remain readable (due to --no-read-protect)

Check all blocks for burn...
idx, BLOCK_NAME, Conclusion
[00] BLOCK0 is not empty
(written ): 0x000000008000000000000000000000000000000000000000
(to write): 0x000000000000000000000400000000000000000000001000
(coding scheme = NONE)
[08] BLOCK_KEY4 is empty, will burn the new value
.
This is an irreversible operation!
Type 'BURN' (all capitals) to continue.
BURN
Error in BLOCK8, re-burn it again (#0), to fix it. fail_bit=1, num_errors=0
Error in BLOCK8, re-burn it again (#1), to fix it. fail_bit=1, num_errors=0
Error in BLOCK8, re-burn it again (#2), to fix it. fail_bit=1, num_errors=0

A fatal error occurred: Burn BLOCK_KEY4 (['BLOCK8']) was not successful

A bit more than half of the key is written correctly in BOCK8 / BLOCK_KEY4
under in the summary:
Error(s) in BLOCK8 [ERRORS:0 FAIL:1]

BLOCK0 ( ) [0 ] err__regs: 00000000 00000000 00000000 00000000 00000000 00000000
EFUSE_RD_RS_ERR0_REG 0x00000000
EFUSE_RD_RS_ERR1_REG 0x00000008

[KonstantinKondrashov]

Hi @Daphne-HU!
You described two cases:

1. nothing is burned in BLOCK_KEY4
2. partially burned a key in BLOCK_KEY4
   (BLOCK0 is not updated too. So write and read protection bits for the key block are not set, for both cases).

What is the difference between the two cases?

It looks like it is a hardware issue.

[Daphne-HU]

@KonstantinKondrashov
Thanks for your response!
I’m seeing different cases on different devices, some work some don't.
On most devices that do not work i get case 1. Nothing is burned in BLOCK_KEY4.
All the devices have the same PCB design.

Do you have any idea what hardware issue this could be?
I tried powering it with a stable external power supply, but that didn’t make any difference.