diff --git a/bucket/7zip.json b/bucket/7zip.json
index 105f68d6..0c6d0251 100644
--- a/bucket/7zip.json
+++ b/bucket/7zip.json
@@ -2,6 +2,17 @@
 	"homepage": "http://www.7-zip.org/",
 	"license": "http://www.7-zip.org/license.txt",
 	"version": "9.20",
-	"url": "http://downloads.sourceforge.net/sevenzip/7za920.zip",
-	"bin": "7za.exe"
+	"architecture": {
+		"64bit": {
+			"url": "http://downloads.sourceforge.net/project/sevenzip/7-Zip/9.20/7z920-x64.msi",
+			"hash": { "sha256": "62df458bc521001cd9a947643a84810ecbaa5a16b5c8e87d80df8e34c4a16fe2" },
+			"msi": { "code": "{23170F69-40C1-2702-0920-000001000000}" }
+		},
+		"32bit": {
+			"url": "http://downloads.sourceforge.net/project/sevenzip/7-Zip/9.20/7z920.msi",
+			"hash": { "sha256": "fe4807b4698ec89f82de7d85d32deaa4c772fc871537e31fb0fccf4473455cb8" },
+			"msi": { "code": "{23170F69-40C1-2701-0920-000001000000}" }
+		}
+	},
+	"bin": "7z.exe"
 }
\ No newline at end of file
diff --git a/lib/install.ps1 b/lib/install.ps1
index a0eb6817..9f7adb2c 100644
--- a/lib/install.ps1
+++ b/lib/install.ps1
@@ -137,7 +137,8 @@ function run_installer($fname, $manifest, $architecture, $dir) {
 			}
 			if(!($msi.code)) { abort "error in manifest: couldn't find MSI code"}
 			$exe = 'msiexec'
-			$arg = @("/i `"$msifile`"", '/qb-!', "TARGETDIR=`"$dir`"") + $msi.args
+			$arg = @("/i `"$msifile`"", '/qb-!', "TARGETDIR=`"$dir`"", "INSTALLDIR=`"$dir`"") +
+				(@($msi.args) | ? { $_ })
 		} elseif($installer) { # other installer
 			$rmfile = $exe = "$dir\$(coalesce $installer.exe "$fname")"
 			if(!(is_in_dir $dir $exe)) {
@@ -163,7 +164,7 @@ function run_uninstaller($manifest, $architecture, $dir) {
 
 		if($msi) {
 			$code = $msi.code
-			$exe = "msiexec"; $arg = @("/x $code", '/quiet');
+			$exe = "msiexec"; $arg = @("/x $code", '/qb-!');
 			$continue_exit_codes.1605 = 'not installed, skipping'
 		} elseif($uninstaller) {
 			$exe = "$dir\$($uninstaller.exe)"