Well, finding the codes is just the first step. Are you already familiar with
(1) how to use the JP1 tools to create an upgrade, and
(2) how to convert it into a Sling-usable BIN file, and
(3) how to then modify the .cfg file to allow you to select this new upgrade for your Sling?
If the answer to (1) is NO, read the "Beginners, Read this Thread First" sticky post (linked at the bottom).
If the answer to (1) is YES, then try
THIS UPGRADE for a Sony DVD megachanger (there are a couple more in the File section, as well), which has a disc skip/select function. It provides the following:
disk skip + EFC 177, OBC 062
disk skip - EFC 175, OBC 061
Disc 1 EFC 034, OBC 064
Disc 2 EFC 030, OBC 065
Disc 3 EFC 032, OBC 066
Disc 4 EFC 028, OBC 067
Disc 5 EFC 035, OBC 068
For number (2) and/or (3), if the answer is NO, then read the FIRST (sticky) POST in this forum about upgrading your Sling files.
(and if the answer is YES, then you should be all set, right?)