Using !packhdr

Author: Afrow UK (talk, contrib)

!packhdr

!packhdr is a useful compile time directive which allows modifications to the built installer executable header before it is written to the finished installer executable file. It can be used in conjunction with some useful batch files to:

• Pack the header (UPX)
• Remove the installer icon (Resource Hacker)
• Add additional supported OS GUIDs for Windows 8 and above detection in NSIS 2.46

Download

1. Extract the contents of Packhdr.zip (2 KB) to your NSIS directory
2. Download UPX and Resource Hacker and copy upx.exe and reshacker.exe to the NSIS\Packhdr folder

Usage

!define Packhdr noicon+upx
!define RequestExecutionLevel admin
!include Packhdr.nsh

For all NSIS versions

• !define Packhdr upx for all installers to reduce their header size.
• !define Packhdr noicon+upx for installers or utilities written in NSIS that do not require an icon.
• !define Packhdr noicon for when you do not require an icon and have appended client data to the end of the executable that you do not want to compress.

For NSIS 2.46

• !define RequestExecutionLevel is a replacement for the RequestExecutionLevel installer attribute while also embedding the additional supported OS GUIDs. Supported values are admin, user and highest.

For NSIS 3.0+

• You don't need to use the RequestExecutionLevel define; use the ManifestSupportedOS installer attribute (in conjunction with RequestExecutionLevel) instead.