ESP32 external backup flash

[bluebirdsoftware]

Hello,

I am using an ESP32 with the posibility do update over te air via a http server. I want to prevent update corruption as much as possible and i am having the idea of having an extra flash memory on my pcb (a few mb's) with a default base firmware installed.

When the ESP32 is unable to startup again, i would hold a button when powering on or something, the customer flash memory would be used to rewrite the software to the main ESP32 flash and it would but up again.

Is this, or another alternative possible?
I know a lot of devices have a hard reset button which "reinstalls" everything like it was in the factory but i am not sure if this can work on an ESP32 too.

Thanks already for any advice

[WiFive]

There is already support for a factory partition and multiple ota partitions and other features to prevent bad ota updates so it is easier to use a bigger main flash chip but if you have to use a second flash chip you could make a custom bootloader to do what you want.

[bluebirdsoftware]

Thank you for your reply.
If i can use the internal storage that would be great too.

I don't quiet understand the partitions in ESP32.
My firmware now (which is not done yet) shows this:

RAM: [= ] 11.5% (used 37632 bytes from 327680 bytes)
Flash: [===== ] 51.1% (used 669303 bytes from 1310720 bytes)


I cannot figure out how the partitions are devided and maybe i can change this. If i remember correctly, the ESP32 i have is 16MB, but if not i can buy 16MB versions in the future.

Do you have any information / tips on how to devide de partitions correctly and how to have a backup firmware to prevent bad ota?