ESP32 S2 flashes but monitor shows invalid header: 0xffffff0f error

[dininduwara]

Hi!

I just ordered my first ESP32 S2 development board (ESP32-S2 Saola 1R Dev Kit featuring ESP32-S2 WROVER https://core-electronics.com.au/esp32-s ... rover.html)

However after flashing the hello_world program using the idf.py tool, I get the following error:

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ESP-ROM:esp32s2-rc4-20191025
Build:Oct 25 2019
rst:0x1 (POWERON),boot:0x1f (SPI_FAST_FLASH_BOOT)
invalid header: 0xffffff0f
invalid header: 0xffffff0f //spams this continuously

The tool appears to flash everything correctly, but all I get "invalid header: 0xffffff0f" spammed on my console.

Any help would be appreciated. Thanks!

[Sprite]

How exactly are you flashing this? It feels like you only flashed the app, not the bootloader.

[chegewara]

How about strapping pins? It looks to me like you may have some pins in wrong state.

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rst:0x1 (POWERON),boot:0x1f (SPI_FAST_FLASH_BOOT)

Here is normal boot:

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rst:0x1 (POWERON),boot:0x8 (SPI_FAST_FLASH_BOOT)

[dininduwara]

How exactly are you flashing this? It feels like you only flashed the app, not the bootloader.

I'm flashing it via usb, following the documentation here: https://docs.espressif.com/projects/esp ... ep-by-step

[dininduwara]

How about strapping pins? It looks to me like you may have some pins in wrong state.

Code: Select all

rst:0x1 (POWERON),boot:0x1f (SPI_FAST_FLASH_BOOT)

Here is normal boot:

Code: Select all

rst:0x1 (POWERON),boot:0x8 (SPI_FAST_FLASH_BOOT)

Sorry for the newb question, but how would I do that?

[Sprite]

I'm flashing it via usb, following the documentation here: https://docs.espressif.com/projects/esp ... ep-by-step

So just to check, you're using 'idf.py -p PORT flash', and not app_flash or some other idf.py command? Do you get any warnings while flashing?

[dininduwara]

Thank you all for the responses.
After some tinkering I randomly managed to get it to work.

First I flashed, then held down the boot btn, press reset and then disconnect power and reconnect. I had tried all these steps previously, but it only worked in this order.

[timc100]

To help anyone else facing the same problem, I bumped into this issue whilst trying to use up some ESP32 S2's on a project.

The reason is simply that there are some strapping pins that are defined in the manual, they are IO0, IO45 and IO46. These control how the ESP32 boots up.

IO45 controls the voltage used for the on-board SPI flash. By default its pulled down to logic 0 with a weak internal pull-down resistor, this setting makes the SPI power supply 3.3V, but when pulled high, it drops the SPI supply to 1.8V. This explains why the result is mostly F's as the bus is floating with the device not powered properly.

Also avoid IO26, which is the PSRAM CS pin. I've had problems with this before too.

The ability to use these pins depends on which varient of the ESP32 you have, since not all have external FLASH or have PSRAM fitted. When they are not fitted, then these pins can be used.

Its easy when switching between ESP32 chip versions to overlook this, as there is always a shortage of free IO pins in projects.