Mod 7, according to Garmin Service Bulletin No.: 0532 Revision B, needs to be performed.
This Service Bulletin (SB No.: 0532 Rev B) describes procedures to perform an alteration to and means to obtain installation and operational approval for use of added TERRAIN functionality. This TERRAIN functionality dos NOT perform the functions of Terrain Awareness and Warning System (TAWS) and does NOT meet the performance requirements established under TSO-C151(), and is not intended to substitute for TAWS.
Approval for unit alteration and operational use of TERRAIN function is by Supplemental Type Certification (STC), SA00800WI (GPS-400), SA00801WI (GNC-420/420A), or SA00705WI (GNS-430/430A), as applicable.