Support reading flash

[t-moe]

It would be nice if espflash could read back the flash into a file.
Currently I have to rely on esptool.py to read back flash segments... Probe-rs is also not able to do this.

[SergioGasquez]

Hi! Just opened #558, mind verifying that it works properly for you?

[t-moe]

Surprising! I didn't anticipate the implementation (requested by me) to happen so quickly. Big thanks @SergioGasquez ! Everything is functioning seamlessly. 🎉

((Yes, I still had to manually put the device into bootloader mode, because of esp-rs/esp-flasher-stub#45 ))

[SergioGasquez]

Surprising! I didn't anticipate the implementation (requested by me) to happen so quickly. Big thanks @SergioGasquez ! Everything is functioning seamlessly. 🎉

((Yes, I still had to manually put the device into bootloader mode, because of esp-rs/esp-flasher-stub#45 ))

Thanks for the testing! I'll try to investigate the bootloader issue in the upcoming days