In “Tools of the Trade”, replace “The Hack Value of a Tool is defined by its subroutines. Where a Tool contains multiple versions of the same subroutine, its effects are cumulative unless otherwise stated.” with:-

When the Hack Value of a Tool is calculated by a Hacker, it starts at zero and then has the effects of each of its Subroutines applied once in the order that they are listed in the Tool’s GNDT field.

Add a subroutine to the list:

• 2 - Amplifier - If this is the leftmost Amplifier in the Tool, then the Hack Value of this Tool is doubled.