Hi @torntrousers,

Please try using the below setup:

A) Define WOLFSSL_USER_SETTINGS globally or at the top of <wolfssl/wolfcrypt/settings.h> so that settings.h will look for and include the file "user_settings.h"
B) Create an empty header "user_settings.h" and use this file to tune the build
C) Include <wolfssl/wolfcrypt/settings.h> in your application
D) Update the include path for your project so "user_settings.h" can be included by settings.h.
E) Setup a custom function to seed the wolfSSL RNG with your own entropy source

// Define the type your function will be returning, for this example we'll return an unsigned int
 #define CUSTOM_RAND_TYPE      unsigned int

// Your function that provides entropy seed to "seed" the RNG declare as an extern
 extern unsigned int my_rng_seed_gen(void);

// define the wolfSSL CUSTOM_RAND_GENERATE to be your function
 #undef  CUSTOM_RAND_GENERATE
 #define CUSTOM_RAND_GENERATE  my_rng_seed_gen

Let me know if this helps.

Warm Regards,

K