Make boot disk modified

[Sauro Cesaretti]

Hi,
I'd like to modify a boot disk adding brltty support, so I can pass the
parameter at the kernel startup or
I can startup automatically brltty support.
Could you give me the basic step?
I know that it is possible but I don't know How can do it.
Thanks in advance for this information.
Yours Sincerely.
S. Cesaretti