Fill Blank Cells In A Column With Preceding Value

I have been using this code I found awhile back to fill blank cells in a column with the preceding value. but it leaves the very last cell blank. Like this.

A
B

41055182
905182

41054750
905182

[Code] ........

Is there a way to add possibly a "Do until column B is null or """?

Code:
Sub FillBlanks()
Dim rRange1 As Range, rRange2 As Range
Dim iReply As Integer
If Selection.Cells.Count = 1 Then
MsgBox "You must select your list and include the blank cells", vbInformation, "OzGrid.com"

[Code] ........