How to boot into development kernel from KDK?

Hi,

I have a MacBook Pro M1 that I'm trying to boot development kernel. The SW version is:

ProductName:	macOS
ProductVersion:	11.4
BuildVersion:	20F71

I follow /Library/Developer/KDKs/KDK_11.4_20F71.kdk/KDK_ReadMe.rtfd/TXT.rtf and disabled SIP and authenticated-root. I also copy over the kernels to a livemohnt and update nvram: nvram boot-args="-v kcsuffix=development"

Despite above changes, after reboot, I still don't see the OS booting using development kernel (sysctl kern.osbuildconfig shows I'm still running release.)

Anyone has any luck to enable development/debug/custom kernels on Big Sur?