diff --git a/board/libre-computer/aml-a311d-cc/aml-a311d-cc.c b/board/libre-computer/aml-a311d-cc/aml-a311d-cc.c
index e45cfd5d8a3..294f78858a7 100644
--- a/board/libre-computer/aml-a311d-cc/aml-a311d-cc.c
+++ b/board/libre-computer/aml-a311d-cc/aml-a311d-cc.c
@@ -29,7 +29,7 @@ struct efi_capsule_update_info update_info = {
 #if IS_ENABLED(CONFIG_SET_DFU_ALT_INFO)
 void set_dfu_alt_info(char *interface, char *devstr)
 {
-	if (strcmp(interface, "ram") == 0)
+	if (interface && strcmp(interface, "ram") == 0)
 		env_set("dfu_alt_info", "fitimage ram 0x08080000 0x4000000");
 	else if (IS_ENABLED(CONFIG_EFI_HAVE_CAPSULE_SUPPORT))
 		env_set("dfu_alt_info", update_info.dfu_string);
diff --git a/board/libre-computer/aml-s805x-ac/aml-s805x-ac.c b/board/libre-computer/aml-s805x-ac/aml-s805x-ac.c
index 94cf5b4361f..1ec9a5b401e 100644
--- a/board/libre-computer/aml-s805x-ac/aml-s805x-ac.c
+++ b/board/libre-computer/aml-s805x-ac/aml-s805x-ac.c
@@ -36,7 +36,7 @@ struct efi_capsule_update_info update_info = {
 #if IS_ENABLED(CONFIG_SET_DFU_ALT_INFO)
 void set_dfu_alt_info(char *interface, char *devstr)
 {
-	if (strcmp(interface, "ram") == 0)
+	if (interface && strcmp(interface, "ram") == 0)
 		env_set("dfu_alt_info", "fitimage ram 0x08080000 0x4000000");
 	else if (IS_ENABLED(CONFIG_EFI_HAVE_CAPSULE_SUPPORT))
 		env_set("dfu_alt_info", update_info.dfu_string);
diff --git a/board/libre-computer/aml-s905d3-cc/aml-s905d3-cc.c b/board/libre-computer/aml-s905d3-cc/aml-s905d3-cc.c
index f641db5a494..b552035ee03 100644
--- a/board/libre-computer/aml-s905d3-cc/aml-s905d3-cc.c
+++ b/board/libre-computer/aml-s905d3-cc/aml-s905d3-cc.c
@@ -29,7 +29,7 @@ struct efi_capsule_update_info update_info = {
 #if IS_ENABLED(CONFIG_SET_DFU_ALT_INFO)
 void set_dfu_alt_info(char *interface, char *devstr)
 {
-	if (strcmp(interface, "ram") == 0)
+	if (interface && strcmp(interface, "ram") == 0)
 		env_set("dfu_alt_info", "fitimage ram 0x08080000 0x4000000");
 	else if (IS_ENABLED(CONFIG_EFI_HAVE_CAPSULE_SUPPORT))
 		env_set("dfu_alt_info", update_info.dfu_string);