BA7NXV https://github.com/losehu/uv-k5-firmware-custom/releases Losehu's firmware. Additionally, there's a dedicated thread on the forum where he discusses his firmware, which you can search for.
DF4_9460 BG7QZT The "K5web" website allows you to directly flash firmware (the website integrates firmware and flashing/frequency writing tools). [www.k5vicicode.com] (https://) (Is that right?)
P_Lorenzo https://k5.vicicode.cn/#/chirp/base The website offers various versions, allowing users to flash them as needed.