You can use the UV-K5 custom firmware made by F4HWN which works with SA818
*Armel F4HWN: For Quansheng K5 users with an SA818 based hotspot, special .sa818.bin versions are available in the archive directory. These versions avoid the squelch tail. However, you must first activate Close Tail Command on the SA818.
firmware is :
main github page for this custom firmware: