Ways to deal with 4MB flash limit

[iranl]

We are running into the limits of the 4MB flash (of which 1920kb x 2 to allow for OTA updating is available)
The ESP32 build currently already occupies 94% of the available 1920kb.
Arduino Core 3.0 requires even more flash than Core 2.0.14 and there are still many features to be implemented.

I see a couple of solutions to deal with this and I am wondering what options are prefered by others and if any other solutions are possible.

• Only support 8MB+ devices moving forward
  • Pro: No changes necessary except changing partition table
  • Con: Most users probably use ESP32 devices with 4MB flash
• Different versions for 4MB and 8MB+ devices with different functionality
  • Con: Extra work to support multiple versions
• Try to reduce flash usage
  • Pro: Will not require any action on the part of the user
  • Con: Difficult to reduce flash usage by a meaningfull amount
• Different partition sizes for app0 (big) and app1 (small) with Nuki Hub on app0 and the OTA updater on app1
  • Pro: Will allow for more room for Nuki Hub on 4MB devices
  • Con: Will require current users to flash via USB/serial once to change partition table

[iranl]

Arduino Core 3 PR will move to the last option with a big-small app design