diff --git a/build-docker.sh b/build-docker.sh
index 42db1c5e1..c5793434d 100755
--- a/build-docker.sh
+++ b/build-docker.sh
@@ -5,7 +5,7 @@ if [ "$1" = "--gcc_source" ]; then
   TOOLCHAIN_FLAVOR=src
   shift
 else
-  TOOLCHAIN_FLAVOR=linux
+  TOOLCHAIN_FLAVOR=x86_64-linux
 fi
 
 IMAGE=trezor-firmware-build.$TOOLCHAIN_FLAVOR
diff --git a/ci/Dockerfile b/ci/Dockerfile
index 4391727c8..d0a4afa0d 100644
--- a/ci/Dockerfile
+++ b/ci/Dockerfile
@@ -2,7 +2,7 @@
 
 FROM debian:10
 
-ARG TOOLCHAIN_FLAVOR=linux
+ARG TOOLCHAIN_FLAVOR=x86_64-linux
 ENV TOOLCHAIN_FLAVOR=${TOOLCHAIN_FLAVOR}
 
 ARG FULLDEPS_TESTING=0
@@ -69,16 +69,16 @@ RUN if [ "${TOOLCHAIN_FLAVOR}" = "src" ]; then \
 
 # download toolchain
 
-ENV TOOLCHAIN_LONGVER=gcc-arm-none-eabi-8-2019-q3-update
-ENV TOOLCHAIN_SUBDIR="8-2019q3/RC1.1"
+ENV TOOLCHAIN_LONGVER=gcc-arm-none-eabi-9-2019-q4-major
+ENV TOOLCHAIN_SUBDIR="9-2019q4/RC2.1"
 ENV TOOLCHAIN_URL=https://developer.arm.com/-/media/Files/downloads/gnu-rm/${TOOLCHAIN_SUBDIR}/${TOOLCHAIN_LONGVER}-${TOOLCHAIN_FLAVOR}.tar.bz2
-ENV TOOLCHAIN_HASH_linux=b50b02b0a16e5aad8620e9d7c31110ef285c1dde28980b1a9448b764d77d8f92
-ENV TOOLCHAIN_HASH_src=e8a8ddfec47601f2d83f1d80c0600f198476f227102121c8d6a5a781d0c2eeef
+ENV TOOLCHAIN_HASH_linux=bcd840f839d5bf49279638e9f67890b2ef3a7c9c7a9b25271e83ec4ff41d177a
+ENV TOOLCHAIN_HASH_src=f162a655f222319f75862d7aba9ff8a4a86f752392e4f3c5d9ef2ee8bc13be58
 
 # extract toolchain
 
 RUN cd /opt && wget --no-verbose ${TOOLCHAIN_URL}
-RUN cd /opt && echo "${TOOLCHAIN_HASH_linux} ${TOOLCHAIN_LONGVER}-linux.tar.bz2\n${TOOLCHAIN_HASH_src} ${TOOLCHAIN_LONGVER}-src.tar.bz2" | sha256sum -c --ignore-missing
+RUN cd /opt && echo "${TOOLCHAIN_HASH_linux} ${TOOLCHAIN_LONGVER}-x86_64-linux.tar.bz2\n${TOOLCHAIN_HASH_src} ${TOOLCHAIN_LONGVER}-src.tar.bz2" | sha256sum -c --ignore-missing
 RUN cd /opt && tar xfj ${TOOLCHAIN_LONGVER}-${TOOLCHAIN_FLAVOR}.tar.bz2
 
 # build toolchain (if required)