diff --git a/src/fundamental/chid-fundamental.c b/src/fundamental/chid-fundamental.c
index 47eabdb349..a99d0dae64 100644
--- a/src/fundamental/chid-fundamental.c
+++ b/src/fundamental/chid-fundamental.c
@@ -15,6 +15,7 @@
  */
 
 #if SD_BOOT
+#  include "efi-string.h"
 #  include "util.h"
 #else
 #  include <byteswap.h>
diff --git a/src/fundamental/chid-fundamental.h b/src/fundamental/chid-fundamental.h
index 48b1343f5c..81c40e087f 100644
--- a/src/fundamental/chid-fundamental.h
+++ b/src/fundamental/chid-fundamental.h
@@ -3,7 +3,7 @@
 #pragma once
 
 #if SD_BOOT
-#  include "efi-string.h"
+#  include "efi.h"
 #else
 #  include <uchar.h>
 #endif
diff --git a/src/fundamental/sha1-fundamental.c b/src/fundamental/sha1-fundamental.c
index 0f631d5053..b8d100ff6b 100644
--- a/src/fundamental/sha1-fundamental.c
+++ b/src/fundamental/sha1-fundamental.c
@@ -76,6 +76,12 @@ Still 100% public domain
 modified for use with systemd
 */
 
+#if SD_BOOT
+#  include "efi-string.h"
+#else
+#  include <string.h>
+#endif
+
 #include "memory-util-fundamental.h"
 #include "sha1-fundamental.h"
 
diff --git a/src/fundamental/sha256-fundamental.c b/src/fundamental/sha256-fundamental.c
index 9f8b0106fe..108c43b45a 100644
--- a/src/fundamental/sha256-fundamental.c
+++ b/src/fundamental/sha256-fundamental.c
@@ -21,6 +21,12 @@
    License along with the GNU C Library; if not, see
    <https://www.gnu.org/licenses/>.  */
 
+#if SD_BOOT
+#  include "efi-string.h"
+#else
+#  include <string.h>
+#endif
+
 #include "assert-fundamental.h"
 #include "macro-fundamental.h"
 #include "memory-util-fundamental.h"