If you want to be aware continuously, you have to not pay so much attention to the object, and pay more attention to the awareness instead.
So, as you’re walking, just check to see what the mind is aware of. Is the mind aware? What is the mind aware of? Then, even if you should lose awareness of the footsteps, you’ll know that the mind is aware of something else.
So, it doesn’t feel like you have lost awareness; the awareness is continuous and you’ll know where the mind has gone to.