diff --git a/.toolversions b/.toolversions
index fd4b736d1..adc296916 100644
--- a/.toolversions
+++ b/.toolversions
@@ -1,2 +1,2 @@
-microsoft.dotnet.buildtools=1.0.26-prerelease-00802-01
+microsoft.dotnet.buildtools=1.0.26-prerelease-00926-02
 microsoft.dotnet.buildtools.run=1.0.0-prerelease-00807-04
\ No newline at end of file
diff --git a/build.proj b/build.proj
index 522844b34..987b159a4 100644
--- a/build.proj
+++ b/build.proj
@@ -68,7 +68,11 @@
           Inputs="$(DotnetCliBuildDirectory)/dotnet-cli-build.csproj"
           Outputs="@(RestoreDotnetCliBuildFrameworkOutputs)">
 
-    <Exec Command="$(DotnetStage0) restore3" WorkingDirectory="$(DotnetCliBuildDirectory)"/>
+    <PropertyGroup>
+      <ExtraRestoreArgs Condition="'$(OS)' != 'Windows_NT'">$(ExtraRestoreArgs) --disable-parallel</ExtraRestoreArgs>
+    </PropertyGroup>
+
+    <Exec Command="$(DotnetStage0) restore3 $(ExtraRestoreArgs)" WorkingDirectory="$(DotnetCliBuildDirectory)"/>
   </Target>
 
   <Target DependsOnTargets="$(CLITargets)" Name="BuildTheWholeCli"></Target>
diff --git a/build_projects/dotnet-cli-build/DotNetRestore.cs b/build_projects/dotnet-cli-build/DotNetRestore.cs
index cb75d513a..888485d47 100644
--- a/build_projects/dotnet-cli-build/DotNetRestore.cs
+++ b/build_projects/dotnet-cli-build/DotNetRestore.cs
@@ -12,7 +12,7 @@ namespace Microsoft.DotNet.Cli.Build
 
         protected override string Args
         {
-            get { return $"{GetSource()} {GetPackages()} {GetSkipInvalidConfigurations()}"; }
+            get { return $"{GetSource()} {GetPackages()} {GetSkipInvalidConfigurations()} {GetDisableParallel()}"; }
         }
 
         public string Source { get; set; }
@@ -50,5 +50,10 @@ namespace Microsoft.DotNet.Cli.Build
 
             return null;
         }
+
+        private string GetDisableParallel()
+        {
+            return "--disable-parallel";
+        }
     }
 }
diff --git a/build_projects/dotnet-cli-build/DotNetRestoreProjectJson.cs b/build_projects/dotnet-cli-build/DotNetRestoreProjectJson.cs
index d22982093..81f70d15f 100644
--- a/build_projects/dotnet-cli-build/DotNetRestoreProjectJson.cs
+++ b/build_projects/dotnet-cli-build/DotNetRestoreProjectJson.cs
@@ -12,7 +12,7 @@ namespace Microsoft.DotNet.Cli.Build
 
         protected override string Args
         {
-            get { return $"{GetVerbosity()} {GetFallbackSource()} {GetPackages()}"; }
+            get { return $"{GetVerbosity()} {GetFallbackSource()} {GetPackages()} {GetDisableParallel()}"; }
         }
 
         public string FallbackSource { get; set; }
@@ -50,5 +50,10 @@ namespace Microsoft.DotNet.Cli.Build
 
             return null;
         }
+
+        private string GetDisableParallel()
+        {
+            return "--disable-parallel";
+        }
     }
 }
diff --git a/run-build.sh b/run-build.sh
index 37504a6bb..c842f7e2a 100755
--- a/run-build.sh
+++ b/run-build.sh
@@ -132,6 +132,9 @@ done < "$REPOROOT/branchinfo.txt"
 [ -z "$DOTNET_INSTALL_DIR" ] && export DOTNET_INSTALL_DIR=$REPOROOT/.dotnet_stage0/$ARCHITECTURE
 [ -d "$DOTNET_INSTALL_DIR" ] || mkdir -p $DOTNET_INSTALL_DIR
 
+# During xplat bootstrapping, disable HTTP parallelism to avoid fatal restore timeouts.
+export __INIT_TOOLS_RESTORE_ARGS="$__INIT_TOOLS_RESTORE_ARGS --disable-parallel"
+
 DOTNET_SKIP_FIRST_TIME_EXPERIENCE=1
 toolsLocalPath="$REPOROOT/build_tools"
 bootStrapperPath="$toolsLocalPath/bootstrap.sh"