diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 704c0fd4..9c9bc72a 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -13,7 +13,7 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        os: [windows-latest, macos-latest]
+        os: [ubuntu-latest, windows-latest, macos-latest]
 
     steps:
       - uses: actions/checkout@v2
@@ -41,8 +41,11 @@ jobs:
         with:
           package-dir: python 
         env:
-          CIBW_SKIP: "cp27-* pp*-macosx* cp35-macosx_x86_64"
+          CIBW_SKIP: "cp27-* cp36-* *-musllinux* pp*-macosx* cp35-macosx_x86_64"
+          CIBW_MANYLINUX_X86_64_IMAGE: "manylinux_2_28"
+          CIBW_BEFORE_BUILD_LINUX: "yum update -y && yum install -y libusb-devel"
           CIBW_BUILD_VERBOSITY: 3
+          CIBW_ARCHS_LINUX: "x86_64"
           CIBW_ARCHS_MACOS: "x86_64 arm64"
           # Skip trying to test arm64 builds on Intel Macs
           CIBW_TEST_SKIP: "*-macosx_arm64 *-macosx_universal2:arm64"
diff --git a/lib/atca_platform.h b/lib/atca_platform.h
index ccd2588a..39d9757c 100644
--- a/lib/atca_platform.h
+++ b/lib/atca_platform.h
@@ -28,6 +28,7 @@
 #define ATCA_PLATFORM_H
 
 #include <stddef.h>
+#include <string.h>
 
 #if defined(ATCA_TESTS_ENABLED) || !defined(ATCA_PLATFORM_MALLOC)
 void*   hal_malloc(size_t size);
@@ -36,22 +37,20 @@ void    hal_free(void* ptr);
 #define hal_malloc      ATCA_PLATFORM_MALLOC
 #define hal_free        ATCA_PLATFORM_FREE
 #endif
-#endif
 
 #ifdef ATCA_PLATFORM_MEMSET_S
 #define hal_memset_s    ATCA_PLATFORM_MEMSET_S
 #else
-#include <string.h>
 #ifndef memset_s
 #define hal_memset_s    atcab_memset_s
 #else
 #define hal_memset_s    memset_s
 #endif
+#endif
 
 #ifdef ATCA_PLATFORM_STRCASESTR
 #define lib_strcasestr  ATCA_PLATFORM_STRCASESTR
 #else
-#include <string.h>
 #ifndef strcasestr
 char *lib_strcasestr(const char *haystack, const char *needle);
 #else
diff --git a/lib/hal/hal_linux_uart_userspace.c b/lib/hal/hal_linux_uart_userspace.c
index 1a998d6d..204a364a 100644
--- a/lib/hal/hal_linux_uart_userspace.c
+++ b/lib/hal/hal_linux_uart_userspace.c
@@ -129,6 +129,7 @@ static ATCA_STATUS hal_uart_open_file(atca_uart_host_t * hal_data, ATCAIfaceCfg
         {
             struct termios tty;
             speed_t rate;
+            int flags;
 
             /* Get existing device attributes */
             tcgetattr(hal_data->fd_uart, &tty);
@@ -190,6 +191,13 @@ static ATCA_STATUS hal_uart_open_file(atca_uart_host_t * hal_data, ATCAIfaceCfg
                 return ATCA_COMM_FAIL;
             }
 
+            flags = TIOCM_DTR;
+            if (-1 == ioctl(hal_data->fd_uart, TIOCMBIS, &flags))
+            {
+                close(hal_data->fd_uart);
+                return ATCA_COMM_FAIL;
+            }
+
             status = ATCA_SUCCESS;
         }
         else
diff --git a/python/cryptoauthlib/atcacert.py b/python/cryptoauthlib/atcacert.py
index 6e083796..5363bd77 100644
--- a/python/cryptoauthlib/atcacert.py
+++ b/python/cryptoauthlib/atcacert.py
@@ -241,7 +241,7 @@ class atcacert_def_t(AtcaStructure):
     """
     CTypes mirror of atcacert_def_t from atcacert_def.h
     """
-    _pack_ = 1
+    pass
 
 # Need to define fields outside the class due to ca_cert_def, which is a pointer
 # to the same class.