RAK3172 FUOTA firmware

I made a custom firmware with RAK3172 and its working well. Now I want to integrate FUOTA in it. but as STM32 lib seems, My code size is already 40% occupied with size optimize. So it is difficult to do FUOTA. Is FUOTA can be done with external storage or any other method.
Is there is proven example to do FUOTA with RAK3172?

Thank You

Welcome to RAK forum @gokat .

We have an on-going R&D (internally) for RAK3172 FUOTA. We understand the challenge on the available memory size. Unfortunately, we do not have the FUOTA feature yet for now.