diff --git a/Makefile b/Makefile
index 86d6e8bb..22c0a159 100644
--- a/Makefile
+++ b/Makefile
@@ -10,7 +10,7 @@ LIBGPIOD_VERSION ?= 1.6.3
 
 USTREAMER_MIN_VERSION ?= $(shell grep -o 'ustreamer>=[^"]\+' PKGBUILD | sed 's/ustreamer>=//g')
 
-DEFAULT_PLATFORM ?= v2-hdmi-rpi4
+DEFAULT_PLATFORM ?= v2-hdmiusb-rpi4
 
 DOCKER ?= docker
 
diff --git a/testenv/Dockerfile b/testenv/Dockerfile
index b0eed89d..9e50ea99 100644
--- a/testenv/Dockerfile
+++ b/testenv/Dockerfile
@@ -79,7 +79,9 @@ RUN pacman --noconfirm --ask=4 -Syy \
 	&& rm -rf /var/cache/pacman/pkg/*
 
 COPY testenv/requirements.txt requirements.txt
-RUN pip config set global.index-url https://pypi.tuna.tsinghua.edu.cn/simple && pip install --break-system-packages -r requirements.txt
+RUN pip config set global.index-url https://pypi.tuna.tsinghua.edu.cn/simple \
+	&& pip install --break-system-packages -r requirements.txt \
+	&& pip cache purge
 
 # https://stackoverflow.com/questions/57534295
 WORKDIR /root
@@ -87,7 +89,8 @@ RUN npm config set registry https://registry.npmmirror.com \
 	&& npm install htmlhint -g \
 	&& npm install pug \
 	&& npm install pug-cli -g \
-	&& npm install @babel/eslint-parser -g
+	&& npm install @babel/eslint-parser -g \
+	&& npm cache clean -f
 WORKDIR /
 
 ARG USTREAMER_MIN_VERSION