diff --git a/AdvancedInstall.md b/AdvancedInstall.md
index f020a15..8ddffcf 100644
--- a/AdvancedInstall.md
+++ b/AdvancedInstall.md
@@ -201,9 +201,11 @@ The following procedure will install and run Tahoe-LAFS on Windows. (This is bas
 
 If the build or install steps result in an error that says a compiler is needed, install the MinGW C/C++ compiler as follows:
 
-1. Download and install MinGW from  http://sourceforge.net/projects/mingw/files/Automated%20MinGW%20Installer/MinGW%205.1.4/MinGW-5.1.4.exe/download. The installer will prompt you for what components to install. You need the base components plus g++.
+1. Download and install MinGW from http://sourceforge.net/projects/mingw/files/ (the main installer linked from the big green download button). The installer will prompt you for what components to install. You need the base components plus g++.
 
-2. Configure distutils to use MinGW. To configure distutils to use mingw32, create a file called "distutils.cfg" in C:\Python25\lib\distutils, and put in that file:
+2. Versions 5.1.x of MinGW have a bug in the bundled Gnu assembler. If typing "`as --version}" at the command line gives "```GNU assembler (GNU Binutils) 2.20`", then you have an affected version. To fix this, download [http://sourceforge.net/projects/mingw/files/GNU%20Binutils/binutils-2.19.1/binutils-2.19.1-mingw32-bin.tar.gz/download binutils-2.19.1-mingw32-bin.tar.gz], and extract it into the MinGW installation directory, overwriting the existing files. Then do "`as --version`" again and check that the result is "`GNU assembler (GNU Binutils) 2.19.1`.
+
+3. Configure distutils to use MinGW. To configure distutils to use mingw32, create a file called "distutils.cfg" in C:\Python25\lib\distutils, and put in that file:
 
 ```
 [build]