[34S] occasional RTC reset upon power on

[Marcus von Cube]

There are plenty of options.

Code:

/// PLL MUL values.
#define PLLMUL_HALF       599   // half speed (20 MHz)
#define PLLMUL_HALF_NX    665   // if no crystal installed
#define PLLMUL_FULL       1124  // (37 MHz) 1199 is probably too demanding on the hardware
#define PLLMUL_FULL_NX    1249  // 1333  // no crystal

You can adjust these lines in main.c for different speeds. See set_speed() for details.