SSP 1.5.2 and GUIX 5.4.1.1 Bootloader Options S7G2-DK

I would like to see if there is a way/framework or an example to get this started:

I am looking for something very basic like the below sequence:

1. On every power cycle the bootloader looks into USB or SD Card for a valid hex file and starts flashing right away.

2. If there is not a valid hex file or no USB detected, the bootloader times out in 2-3 secs and jumps to actual application.

We use SSP 1.5.2 and GUIX 5.4.1.1, S7G2-DK

Any inputs on this is much appreciated.

Thanks,

Sam