Switch -IICON<name> - specify SFX icon
Specify an icon to use in the created or updated SFX archive. The <name> parameter is a name of .ico file. This file must include at least one 32x32 icon, 16 or 256 colors (or both). It is also recommended though not required to include 16x16 icons. Icon sizes larger than 32x32 and colors larger than 256 are not supported in Windows 98 and Me. You must not compress SFX module by any third party executable compressors if you are going to use large icon sizes or color depths.
This switch is the command line equivalent of "Load SFX icon from the file" option in SFX options: Text and icon dialog.
WinRAR a -sfx -iiconc:\myicons\ver1.ico setup.exe c:\myfiles
WinRAR s -iiconc:\myicons\ver2.ico setup.exe