Not able to flash programs to esp32c6 getting "A fatal error occurred: Failed to connect to ESP32-C6: Invalid head of packet (0x66): Possible serial noise or corruption." error (IDFGH-12387)

[arunvarghese12]

Answers checklist.

• I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• I have updated my IDF branch (master or release) to the latest version and checked that the issue is present there.
• I have searched the issue tracker for a similar issue and not found a similar issue.

General issue report

I was using ESP32-C6-MINI-1U with the ESP Prog.
made connections as per below image, as suggested by the document: https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/current-consumption-measurement-modules.html#

But on issuing flash, I'm getting "A fatal error occurred: Failed to connect to ESP32-C6: Invalid head of packet (0x66): Possible serial noise or corruption." error and am not able to flash the programs to the device.

on issuing monitor getting the below response continuously,

invalid header: 0xffffffff
invalid header: 0xffffffff
invalid header: 0xffffffff

Please help resolve this and program the module.

[dobairoland]

Do you experience the same issue without Joulescope connected?

What esptool version are you using?

Please add the --trace argument to the esptool flashing command and share the output.

[arunvarghese12]

Hi,
I'm not using joulescope but directly connecting to a power supply.

I'm not using esptool but ESP IDF 5.2

[dobairoland]

I see only 5 cables going to the module. What is missing?

You can invoke esptool directly. You see the command in the output of idf.py flash.

[arunvarghese12]

6 cables are going, TX, RX, enable, IO0, 3V3 and GND.

I didn't really get what you meant by invoking esptool.

below are the responses I'm getting for --trace command, can you please provide the correct format,

[dobairoland]

cd build
esptool.py --chip esp32c6 --trace write_flash @flash_args

And please send the respose as text file and not as screenshot.

[arunvarghese12]

this is what I'm getting when giving esptool.py --chip esp32c6 --trace write_flash
esptool write_flash: error: the following arguments are required:

what should be @flash_args ?

on giving com as address and deep_sleep bin file as filename,
I'm continuously getting the invalid header response,

PS C:\Espressif\frameworks\esp-idf-v5.2.1-2\examples\system\deep_sleep\build> esptool.py --chip esp32c6 --trace write_flash 6 deep_sleep.bin
esptool.py v4.7.0
Found 4 serial ports
Serial port COM6
Connecting...TRACE +0.000 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
55555555 | UUUU
TRACE +0.002 Write 46 bytes:
c000082400000000 0007071220555555 | ...$........ UUU
5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
5555555555555555 5555555555c0 | UUUUUUUUUUUUU.
TRACE +0.010 Read 1 bytes: 45
TRACE +0.001 Read invalid data: 45
TRACE +0.000 Remaining data in serial buffer:
53502d524f4d3a65 7370333263362d32 | SP-ROM:esp32c6-2
303232303931390d 0a4275696c643a53 | 0220919..Build:S
6570203139203230 32320d0a7273743a | ep 19 2022..rst:
3078312028504f57 45524f4e292c626f | 0x1 (POWERON),bo
6f743a3078382028 5350 | ot:0x8 (SP
.TRACE +0.054 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
55555555 | UUUU
TRACE +0.002 Write 46 bytes:
c000082400000000 0007071220555555 | ...$........ UUU
5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
5555555555555555 5555555555c0 | UUUUUUUUUUUUU.
TRACE +0.007 Read 1 bytes: 6e
TRACE +0.001 Read invalid data: 6e
TRACE +0.000 Remaining data in serial buffer:
76616c6964206865 616465723a203078 | valid header: 0x
6666666666666666 0d0a696e76616c69 | ffffffff..invali
6420686561646572 3a20307866666666 | d header: 0xffff
666666660d0a696e 76616c6964206865 | ffff..invalid he
616465723a203078 6666666666666666 | ader: 0xffffffff
0d0a696e76616c69 6420686561646572 | ..invalid header
3a20307866666666 666666660d0a696e | : 0xffffffff..in
76616c6964206865 616465723a203078 | valid header: 0x
6666666666666666 0d0a696e76616c69 | ffffffff..invali
6420686561646572 3a20307866666666 | d header: 0xffff
666666660d0a696e 76616c6964206865 | ffff..invalid he
616465723a2030 | ader: 0
.TRACE +0.054 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
55555555 | UUUU
TRACE +0.009 Write 46 bytes:
c000082400000000 0007071220555555 | ...$........ UUU
5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
5555555555555555 5555555555c0 | UUUUUUUUUUUUU.
TRACE +0.003 Read 185 bytes:
616465723a203078 6666666666666666 | ader: 0xffffffff
0d0a696e76616c69 6420686561646572 | ..invalid header
3a20307866666666 666666660d0a696e | : 0xffffffff..in
76616c6964206865 616465723a203078 | valid header: 0x
6666666666666666 0d0a696e76616c69 | ffffffff..invali
6420686561646572 3a20307866666666 | d header: 0xffff
666666660d0a696e 76616c6964206865 | ffff..invalid he
616465723a203078 6666666666666666 | ader: 0xffffffff
0d0a696e76616c69 6420686561646572 | ..invalid header
3a20307866666666 666666660d0a696e | : 0xffffffff..in
76616c6964206865 616465723a203078 | valid header: 0x
6666666666666666 0d | ffffffff.
TRACE +0.002 Read invalid data:
616465723a203078 6666666666666666 | ader: 0xffffffff
0d0a696e76616c69 6420686561646572 | ..invalid header
3a20307866666666 666666660d0a696e | : 0xffffffff..in
76616c6964206865 616465723a203078 | valid header: 0x
6666666666666666 0d0a696e76616c69 | ffffffff..invali
6420686561646572 3a20307866666666 | d header: 0xffff
666666660d0a696e 76616c6964206865 | ffff..invalid he
616465723a203078 6666666666666666 | ader: 0xffffffff
0d0a696e76616c69 6420686561646572 | ..invalid header
3a20307866666666 666666660d0a696e | : 0xffffffff..in
76616c6964206865 616465723a203078 | valid header: 0x
6666666666666666 0d | ffffffff.
TRACE +0.001 Remaining data in serial buffer:
.TRACE +0.055 command op=0x08 data len=36 wait_response=1 timeout=0.100 data=
0707122055555555 5555555555555555 | ... UUUUUUUUUUUU
5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
55555555 | UUUU
TRACE +0.005 Write 46 bytes:
c000082400000000 0007071220555555 | ...$........ UUU
5555555555555555 5555555555555555 | UUUUUUUUUUUUUUUU
5555555555555555 5555555555c0 | UUUUUUUUUUUUU.
TRACE +0.009 Read 185 bytes:
666666666666660d 0a696e76616c6964 | fffffff..invalid
206865616465723a 2030786666666666 | header: 0xfffff
6666660d0a696e76 616c696420686561 | fff..invalid hea
6465723a20307866 666666666666660d | der: 0xffffffff.
0a696e76616c6964 206865616465723a | .invalid header:
2030786666666666 6666660d0a696e76 | 0xffffffff..inv
616c696420686561 6465723a20307866 | alid header: 0xf
666666666666660d 0a696e76616c6964 | fffffff..invalid
206865616465723a 2030786666666666 | header: 0xfffff
.....

also the esptool version is, esptool.py v4.7.0

[dobairoland]

what should be @flash_args

It should be passed as is. It would take the arguments from that file.

It doesn't matter. From the output it is clear that reset works but it won't put the chip into download mode. There is some issue with the Boot connection. It might help to hold the BOOT button when starting idf.py flash.

IO0

The Boot pin for ESP32-C6 is IO9 if I'm not mistaken.

[arunvarghese12]

I've changed boot pin to 1O9, still seeing same error, "A fatal error occurred: Failed to connect to ESP32-C6: Invalid head of packet (0x69): Possible serial noise or corruption."

I've first given the boot to IO0 where there was 3V supply, now I've moved it to IO9, does previously giving 3V on IO0 affects anyway?

below is the response I'm getting on giving "esptool.py --chip esp32c6 --trace write_flash @flash_args " command.

PS C:\Espressif\frameworks\esp-idf-v5.2.1-2\examples\system\deep_sleep> cd build
PS C:\Espressif\frameworks\esp-idf-v5.2.1-2\examples\system\deep_sleep\build> esptool.py --chip esp32c6 --trace write_flash @flash_args
usage: esptool write_flash [-h] [--erase-all] [--flash_freq {keep,80m,60m,48m,40m,30m,26m,24m,20m,16m,15m,12m}] [--flash_mode {keep,qio,qout,dio,dout}]
[--flash_size {detect,keep,256KB,512KB,1MB,2MB,2MB-c1,4MB,4MB-c1,8MB,16MB,32MB,64MB,128MB}] [--spi-connection SPI_CONNECTION] [--no-progress] [--verify] [--encrypt]
[--encrypt-files

[ ...]] [--ignore-flash-encryption-efuse-setting] [--force] [--compress | --no-compress]
[ ...]
esptool write_flash: error: the following arguments are required:

[arunvarghese12]

Hi @dobairoland,
any update on this?

[dobairoland]

Yep, sorry. On Windows you need apostrophes as well, i.e. "@flash_args". But this is not causing your problem.

If you insist on flashing modules separately then you can experience such issues. Development boards have additional circuitry to ensure that the chip can be put automatically into download mode. This is obviously not working for you. You need to put the chip manually into download mode. You can read more about this at: https://docs.espressif.com/projects/esptool/en/latest/esp32c6/advanced-topics/boot-mode-selection.html#manual-bootloader (the whole page might be useful for you). As I pointed out earlier, this can be achieved by holding the BOOT button while running the flashing command.

I'm closing this issue because I don't think anything can be done on the software side.

[arunvarghese12]

I tried programming on the development board, but on j5, the current measurement rail. On deep sleep I'm measuring 70uA whereas the datasheet number is 7uA, that's why I moved the evaluation to the module, also the EVK doesn't have an external antenna to evaluate RF parameters of esp32-c6.

I've tries holding BOOT button while programming the device but was facing the same error as "invalid header or packet".

anyway thanks for your response, please update if there is any further debug to be done.

Thanks Again

[dobairoland]

You can try to pull down GPIO9 by connecting it to GND. You don't have to use the BOOT button.

GPIO8 must be pulled up (https://docs.espressif.com/projects/esptool/en/latest/esp32c6/advanced-topics/boot-mode-selection.html#gpio8).

[arunvarghese12]

I have pulled down IO9 by connecting it to GND and have connected IO8 to BOOT,

After that on flashing, below is the response I'm getting, the device is not going to the intended state,

C:\Espressif\frameworks\esp-idf-v5.1.2\examples\system\deep_sleep>idf.py -p COM6 flash
Executing action: flash
Running ninja in directory C:\Espressif\frameworks\esp-idf-v5.1.2\examples\system\deep_sleep\build
Executing "ninja flash"...
[1/5] cmd.exe /C "cd /D C:\Espressif\frameworks\esp-idf-v5.1.2\examples\system\deep_sleep\build\esp-idf\esptool_py && C:\Espressif\python_env\idf5.1_py3.11_env\Scripts\python.exe C:/Espressif/frameworks/esp-idf-v5.1.2/components/partition_table/check_sizes.py --offset 0x8000 partition --type app C:/Espressif/frameworks/esp-idf-v5.1.2/examples/system/deep_sleep/build/partition_table/partition-table.bin C:/Espressif/frameworks/esp-idf-v5.1.2/examples/system/deep_sleep/build/deep_sleep.bin"
deep_sleep.bin binary size 0x23400 bytes. Smallest app partition is 0x100000 bytes. 0xdcc00 bytes (86%) free.
[2/5] Performing build step for 'bootloader'
[1/1] cmd.exe /C "cd /D C:\Espressif\frameworks\esp-idf-v5.1.2\examples\system\deep_sleep\build\bootloader\esp-idf\esptool_py && C:\Espressif\python_env\idf5.1_py3.11_env\Scripts\python.exe C:/Espressif/frameworks/esp-idf-v5.1.2/components/partition_table/check_sizes.py --offset 0x8000 bootloader 0x0 C:/Espressif/frameworks/esp-idf-v5.1.2/examples/system/deep_sleep/build/bootloader/bootloader.bin"
Bootloader binary size 0x55c0 bytes. 0x2a40 bytes (33%) free.
[2/3] cmd.exe /C "cd /D C:\Espressif\frameworks\esp-idf-v5.1.2\components\esptool_py && C:\Espressif\tools\cmake\3.24.0\bin\cmake.exe -D IDF_PATH=C:/Espressif/frameworks/esp-idf-v5.1.2 -D SERIAL_TOOL=C:/Espressif/python_env/idf5.1_py3.11_env/Scripts/python.exe;;C:/Espressif/frameworks/esp-idf-v5.1.2/components/esptool_py/esptool/esptool.py;--chip;esp32c6 -D SERIAL_TOOL_ARGS=--before=default_reset;--after=hard_reset;write_flash;@flash_args -D WORKING_DIRECTORY=C:/Espressif/frameworks/esp-idf-v5.1.2/examples/system/deep_sleep/build -P C:/Espressif/frameworks/esp-idf-v5.1.2/components/esptool_py/run_serial_tool.cmake"
esptool.py --chip esp32c6 -p COM6 -b 460800 --before=default_reset --after=hard_reset write_flash --flash_mode dio --flash_freq 80m --flash_size 2MB 0x0 bootloader/bootloader.bin 0x10000 deep_sleep.bin 0x8000 partition_table/partition-table.bin
esptool.py v4.7.dev3
Serial port COM6
Connecting....
Chip is ESP32-C6FH4 (QFN32) (revision v0.0)
Features: WiFi 6, BT 5, IEEE802.15.4
Crystal is 40MHz
MAC: 40:4c:ca:ff:fe:48:58:78
BASE MAC: 40:4c:ca:48:58:78
MAC_EXT: ff:fe
Uploading stub...
Running stub...
Stub running...
Changing baud rate to 460800
Changed.
Configuring flash size...
Flash will be erased from 0x00000000 to 0x00005fff...
Flash will be erased from 0x00010000 to 0x00033fff...
Flash will be erased from 0x00008000 to 0x00008fff...
Compressed 21952 bytes to 13251...
Writing at 0x00000000... (100 %)
Wrote 21952 bytes (13251 compressed) at 0x00000000 in 0.6 seconds (effective 288.8 kbit/s)...
Hash of data verified.
Compressed 144384 bytes to 75149...
Writing at 0x00010000... (20 %)
Writing at 0x00019b81... (40 %)
Writing at 0x000204a4... (60 %)
Writing at 0x000275a6... (80 %)
Writing at 0x0002efb0... (100 %)
Wrote 144384 bytes (75149 compressed) at 0x00010000 in 2.2 seconds (effective 523.4 kbit/s)...
Hash of data verified.
Compressed 3072 bytes to 103...
Writing at 0x00008000... (100 %)
Wrote 3072 bytes (103 compressed) at 0x00008000 in 0.0 seconds (effective 509.1 kbit/s)...
Hash of data verified.

Leaving...
Hard resetting via RTS pin...
Done

[dobairoland]

have connected IO8 to BOOT,

No, that has to be connected to VCC, not BOOT.

But since you flashed once successfuly, now you can do your measurements with deep sleep.

[dobairoland]

This is from the datasheet of C6:

https://www.espressif.com/sites/default/files/documentation/esp32-c6_datasheet_en.pdf

[arunvarghese12]

But since you flashed once successfuly, now you can do your measurements with deep sleep.

even though I have the previous shared response, the device is not going to sleep,

on giving monitor, below response is what I'm getting,

Enabling timer wakeup, 20s
I (269) gpio: GPIO[0]| InputEn: 1| OutputEn: 0| OpenDrain: 0| Pullup: 0| Pulldown: 0| Intr:0
Enabling GPIO wake����ESP-ROM:esp32c6-20220919
Build:Sep 19 2022
rst:0x1 (POWERON),boot:0x4 (DOWNLOAD(USB/UART0/SDIO_FEI_FEO))
waiting for download

now if I press the BOOT button, it only gives continues log, but still not going to deep sleep

[dobairoland]

This is download mode. This is needed for flashing. See "waiting for download".

You need normal operation mode to application to be executed from flash (SPI boot).

[arunvarghese12]

so after flash, I should keep I08 floating and 109 at boot pin?

[arunvarghese12]

Hi @dobairoland,

I can only flash the device in Download mode but then it is not going to deep sleep state.

How can I configure the module in different states like Deep Sleep?

Regards,
Arun

[dobairoland]

so after flash, I should keep I08 floating and 109 at boot pin?

Not floating. It can be any value according to the table. Not boot pin but 1 (pull-up).

I can only flash the device in Download mode but then it is not going to deep sleep state.

After flashing you need SPI Boot mode to boot into the application which will put it into deep sleep state.

[arunvarghese12]

After flashing you need SPI Boot mode to boot into the application which will put it into deep sleep state.

Is this possible in my case, If yes how?

I tried to move the device from download mode to boot mode by pulling up GPIO9, But then the device is going into some other mode, reading current in nanoAmpheres and then rising it gradually.

[arunvarghese12]

Hi,

If you insist on flashing modules separately then you can experience such issues. Development boards have additional circuitry to ensure that the chip can be put automatically into download mode.

as you suggested, I've flashed the image on the development board, but on configuring deep sleep, I'm measuring 53uA current on the dev kit but according to data sheet the expected Deep Sleep current is 7uA.
Like that on light sleep, I'm measuring 360uA whereas data sheet number is 180uA.