diff --git a/.circleci/config.yml b/.circleci/config.yml
index 8184dc7a8..478bdfa55 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -4,6 +4,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -11,6 +12,8 @@ jobs:
       - run:
           name: Check environment
           command: |
+            env
+            locale -a
             python --version  || true
             python2 --version || true
             python3 --version || true
@@ -30,6 +33,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -43,6 +47,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -56,6 +61,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -69,6 +75,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -82,6 +89,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -95,6 +103,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -108,6 +117,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -121,6 +131,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -134,6 +145,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -147,6 +159,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -160,6 +173,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -173,6 +187,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps:
@@ -186,6 +201,7 @@ jobs:
     docker:
       - image: roboterclubaachen/xpcc-build:latest
     environment:
+      - LANG: "en_US.UTF-8"
       - SCONS_LIB_DIR: "/usr/local/lib/python2.7/dist-packages/scons-2.5.1"
       - SCONSFLAGS: "-j3"
     steps: