This is not currently supported in our BSP. It will require heavvy modifications of the bootloader and also to dedicate a large amount of storage (close to RAM size) to save snapshot data.
Boot time can be improved by reducing the boot.delay parameters to 0 (can save up to 5 seconds from the default configuration, 2 with latest images) and disabling drivers loaded at boot.
This can be done configuring the registry or by building a custom image that includes only the component needed for a specific application.
This second approach could also improve image size, reducing the time required to load in in memory at boot.
We are currently focused in implementing the missing features in the BSP, in the future we will also work on performance optimization, including reducing boot time.