: Improper PLL configuration, or missing external clock. Solution : In system_stm32f4xx.c , set PLL_M and PLL_N for 168MHz operation. Also ensure proper decoupling on VDD.
This is where the open-source alternative firmware enters the picture. la104 firmware work
Unlocking the MiniWare LA104: A Custom Firmware Deep Dive If you’ve picked up a MiniWare LA104 : Improper PLL configuration, or missing external clock
Copy the .hex firmware file (e.g., system.hex ) directly onto the virtual drive. : Improper PLL configuration