How to adjust brake booster pushrod/pin?

Hello all,

I've currently narrowed a problem with my 2008 Mazda3's brake pedal feel down to the brake booster pin, and need to figure out how to adjust the length of the pin.

Based on videos I've watched, many other brake booster pins seem to have a nut on them that allows you to adjust the length, however the booster on the gen1 Mazda3 does not.

I really hope I don't have to remove the booster or go through the pedal box to do this, but I'd appreciate some confirmation or insight here. Cheers.