diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 2d8f2e1..85f5e19 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -54,9 +54,7 @@ jobs:
       - name: Install system libs
         if: runner.os == 'Linux'
         run: |
-          sudo add-apt-repository ppa:ubuntu-toolchain-r/test
-          sudo apt-get update
-          sudo apt-get install libgl1-mesa-dev libxkbcommon-x11-0 libxcb-util-dev g++-9
+          sudo apt-get install libgl1-mesa-dev libxkbcommon-x11-0 libxcb-util-dev
           echo ::set-env name=QMAKE_FLAGS::QMAKE_CXX=g++-9 QMAKE_CC=gcc-9
 
       - name: Get Qt