Need few informations for first 4 KBytes Data into ESP32 Flash

[Ritesh]

Hi Espressif System Developers,

Does anyone has any information like what type of parameters and configurations have been stored into first 4 KBytes of partition into ESP32 Flash?

As Boot loader will be started from 0x1000 location but didn't find much details regarding what parameters and configurations have been stored from 0x0000 to 0x1000 location into ESP32 Flash partition.

I have checked few documents as well as technical reference manual found that there might be EFUSE and other secure flash + bootloader configurations are stored into that partition but still not sure for that.

So, Would you please provide exact details with list of parameters being store into that location?

[Ritesh]

Hi ESP_Angus and Other Espressif System Developers,

Did you guys get sometime to see query which I have sent in my last post? Would you please check that stuff from your side once you get some time?

I have checked into ESP32 Technical Reference Manual and found that first 4 KBytes memory is for Secure Boot and Digest related configuration into Flash Memory.

But, Still, I need more information into details for same.

[WiFive]

https://github.com/espressif/esp-idf/bl ... boot.c#L85

[ESP_Angus]

Hi Ritesh,

As WiFive suggests, the first 192 bytes of the flash is where the digest of the bootloader is stored if secure boot is enabled. The rest of the 4KB is unused (but the whole 4KB is allocated for secure boot due to the need to erase it.) If secure boot is not enabled, this sector is unused.

More details here:
https://docs.espressif.com/projects/esp ... s-overview

and here:
https://docs.espressif.com/projects/esp ... re-support

Efuses are 100% internal to the ESP32 chip itself.

[Ritesh]

Hi ESP_Angus and WiFive,

Thanks for details regarding that. will check and let you know if need any details regarding that.

[Ritesh]

Hi Ritesh,

As WiFive suggests, the first 192 bytes of the flash is where the digest of the bootloader is stored if secure boot is enabled. The rest of the 4KB is unused (but the whole 4KB is allocated for secure boot due to the need to erase it.) If secure boot is not enabled, this sector is unused.

More details here:
https://docs.espressif.com/projects/esp ... s-overview

and here:
https://docs.espressif.com/projects/esp ... re-support

Efuses are 100% internal to the ESP32 chip itself.

Hi,

Thanks for useful information regarding same.

I have just one question like if I erase whole flash then first 4 KBytes blocks of data will be erased in case of secure bootloader configuration is enabled or disabled?