Hello,
I try to use an unused variable inside the bootloader: boot_verbose, but if I put another value than "NO" the kernel consider the value as a "YES" and I got the debug ON at startup.
I am starting looking into the kenv and may be I will find my way with: kernel_options.
I tried to start from the bootloader prompt: boot -yg (try to pass a flag to the kernel) and run kenv but I were unable to find my -yg flag.
I will finaly go to the mailing list on freebsd.
Thanks for your help.