diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index de777d5a3b..4ccaaa47b5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -33,7 +33,7 @@ jobs:
 
     # cpp lint job runs with esphome-lint docker image so that clang-format-*
     # doesn't have to be installed
-    container: esphome/esphome-lint:1.1
+    container: ghcr.io/esphome/esphome-lint:1.1
     steps:
       - uses: actions/checkout@v2
       # Set up the pio project so that the cpp checks know how files are compiled
diff --git a/docker/build.py b/docker/build.py
index 97222df8d1..54a279f845 100755
--- a/docker/build.py
+++ b/docker/build.py
@@ -90,7 +90,7 @@ def main():
                 sys.exit(1)
 
     # detect channel from tag
-    match = re.match(r'\d+\.\d+(?:\.\d+)?(b\d+)?', args.tag)
+    match = re.match(r'^\d+\.\d+(?:\.\d+)?(b\d+)?$', args.tag)
     if match is None:
         channel = CHANNEL_DEV
     elif match.group(1) is None: