diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index ea28e7c2f..877039497 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -17,7 +17,7 @@ on: [push, pull_request]
 
 jobs:
   setup:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
 
     steps:
       - name: Checkout code
@@ -63,7 +63,7 @@ jobs:
           make -C third_party > /dev/null
 
   build:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     needs: setup
     strategy:
       matrix:
@@ -112,7 +112,7 @@ jobs:
           path: build${{ matrix.xlen }}
 
   tests:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     needs: build
     strategy:
       fail-fast: false
@@ -167,7 +167,7 @@ jobs:
           fi
 
   complete:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     needs: tests
 
     steps:
diff --git a/ci/install_dependencies.sh b/ci/install_dependencies.sh
index 4dab27786..38f095da1 100755
--- a/ci/install_dependencies.sh
+++ b/ci/install_dependencies.sh
@@ -31,7 +31,10 @@ check_gcc_version() {
 apt-get update -y
 
 # install system dependencies
-apt-get install -y build-essential valgrind libstdc++6 binutils python3 uuid-dev ccache cmake
+apt-get install -y build-essential valgrind libstdc++6 binutils python3 uuid-dev ccache cmake libffi7
+
+# install yosys synthesis tool
+apt-get install -y yosys
 
 # Check and install GCC 11 if necessary
 if check_gcc_version; then
diff --git a/ci/toolchain_install.sh.in b/ci/toolchain_install.sh.in
index 01ebe889b..99b9111ce 100755
--- a/ci/toolchain_install.sh.in
+++ b/ci/toolchain_install.sh.in
@@ -187,7 +187,6 @@ while [ "$1" != "" ]; do
                 riscv32
                 riscv64
                 sv2v
-                yosys
                 ;;
         -h | --help ) show_usage
                 exit
diff --git a/tests/opencl/common.mk b/tests/opencl/common.mk
index bb7b1e0d6..18485d277 100644
--- a/tests/opencl/common.mk
+++ b/tests/opencl/common.mk
@@ -31,7 +31,7 @@ VX_CFLAGS  += -fno-rtti -fno-exceptions -nostartfiles -nostdlib -fdata-sections
 VX_CFLAGS  += -I$(ROOT_DIR)/hw -I$(VORTEX_HOME)/kernel/include -DXLEN_$(XLEN) -DNDEBUG
 VX_CFLAGS  += -Xclang -target-feature -Xclang +vortex
 VX_CFLAGS  += -Xclang -target-feature -Xclang +zicond
-VX_CFLAGS  += -mllvm -disable-loop-idiom-all
+VX_CFLAGS  += -mllvm -disable-loop-idiom-all	# disable memset/memcpy loop replacement
 #VX_CFLAGS += -mllvm -vortex-branch-divergence=0
 #VX_CFLAGS += -mllvm -print-after-all