How to make your own firmware for Pila87/XM87 Pro keyboard (a barebone mechanical keyboard kit from China)

Since the maker hard-coded the firmware, we can't jump into the bootloader if we don't have the ST-Link. Also, the keyboard itself is missing some parts, and without these parts, we can't use the ST-Link to access the bootloader.

Required parts:

• STLinkv2
• 2 6063 22pF capacitors
• 1 3225 8MHz crystal
• Soldering skill