The original Amber14sb force field was obtained from gromacs user contributions. Please download the force field from there add replace/add the following files in amber14sb_parmbsc1.ff.
aminoacids.rtp
ffbonded_lipid21.itp
ffnonbonded_lipid21.itp
forcefield.itp
ions_at_type.itp
ions.itp
Only the following non-terminal residues have been scaled to 0.78.
ASP
LYS
GLU
ARG