0ff wrote:If it'd be of any help for you, I could send you a working example of OTA update?
No need, it will be redone from scratch. Basically I want it to be like this: You type 'upgrade http://192.168.0.1 80', it fetches all firmware files from external webserver, does any needed security checks and copies them to upper 256KiB of flash. Once the transfer is complete - copies it from the upper to the lower part of flash and erases the upper flash part. Later you can instruct your ESPs to do that automagically once in a while.