diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 3062cca..88abc3a 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -4,7 +4,7 @@ env:
   BUILD_TYPE: Release
 jobs:
   build:
-    runs-on: ubuntu-16.04
+    runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2
         with:
diff --git a/CMakeLists.txt b/CMakeLists.txt
index b397193..576979e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,7 +1,7 @@
 # CMakeLists files in this project can
 # refer to the root source directory of the project as ${SOES_SOURCE_DIR} and
 # to the root binary directory of the project as ${SOES_BINARY_DIR}.
-cmake_minimum_required (VERSION 2.8.4)
+cmake_minimum_required (VERSION 2.8.12)
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake")
 project (SOES)
 
diff --git a/soes/esc.h b/soes/esc.h
index f6f4535..d3beed0 100644
--- a/soes/esc.h
+++ b/soes/esc.h
@@ -573,7 +573,7 @@ typedef struct CC_PACKED
 CC_PACKED_END
 
 CC_PACKED_BEGIN
-typedef struct CC_PACKED
+typedef struct CC_PACKED CC_ALIGNED(4)
 {
    _MBXh mbxheader;
    _COEh coeheader;
@@ -585,7 +585,7 @@ typedef struct CC_PACKED
 CC_PACKED_END
 
 CC_PACKED_BEGIN
-typedef struct CC_PACKED
+typedef struct CC_PACKED CC_ALIGNED(4)
 {
    _MBXh mbxheader;
    _COEh coeheader;
diff --git a/soes/esc_coe.c b/soes/esc_coe.c
index 14b832a..851f8e1 100644
--- a/soes/esc_coe.c
+++ b/soes/esc_coe.c
@@ -1022,8 +1022,8 @@ static void SDO_downloadsegment (void)
             (coesdo->command & COE_TOGGLEBIT);  /* copy toggle bit */
       init_coesdo(coeres, COE_SDORESPONSE, command, 0, 0);
 
-      uint32_t *mbxdata = (uint32_t *)&(coesdo->index);  /* data pointer */
-      copy2mbx (mbxdata, (uint8_t *)ESCvar.data, size);
+      void *mbxdata = &(coesdo->index);  /* data pointer */
+      copy2mbx (mbxdata, ESCvar.data, size);
 
       if (coesdo->command & COE_COMMAND_LASTSEGMENTBIT)
       {
diff --git a/soes/include/sys/gcc/cc.h b/soes/include/sys/gcc/cc.h
index b3067b0..c4598bd 100644
--- a/soes/include/sys/gcc/cc.h
+++ b/soes/include/sys/gcc/cc.h
@@ -32,6 +32,7 @@ extern "C"
 #define CC_PACKED_BEGIN
 #define CC_PACKED_END
 #define CC_PACKED       __attribute__((packed))
+#define CC_ALIGNED(n)   __attribute__((aligned (n)))
 
 #ifdef __rtk__
 #define CC_ASSERT(exp) ASSERT (exp)