How to declare an unsigned 32-bit integer?

The code from the currently accepted answer causes the following error on my system:

This is because PowerShell always tries to convert hex values to int first so even if you cast to uint64, the environment will complain if the number has a negative int value. You can see this from the following example:

PS C:\> [uint64] (-1)
Cannot convert value "-1" to type "System.UInt64". Error: "Value was either too large or too small for a UInt64."
At line:1 char:26
+ Invoke-Expression $ENUS; [uint64] (-1)
+                          ~~~~~~~~~~~~~
    + CategoryInfo          : InvalidArgument: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvalidCastIConvertible

You need to cast the string representation of the number to uint64 to avoid this:

[uint64]"0xff000000" + [uint64]"0xAA"

0xff00000AA is too large for a 32 bit unsigned integer, use uint64

PS> [uint64]0xff00000AA
68451041450

The simplest way is to cast to [uint32] from a long literal (with the L suffix). You don't need to do the math in [uint64] or cast from a string

[uint32]0xff000000L + 0xAA

In PowerShell 6.2 a series of new suffixes have been added including a u suffix fof uint32 so this can be done even simpler

0xff000000u + 0xAA