diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 2e1dda2..cba2385 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -1034,8 +1034,8 @@
 qualifier:
 	/* get the conversion qualifier */
 	spec->qualifier = -1;
-	if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
-	    *fmt == 'Z' || *fmt == 'z' || *fmt == 't') {
+	if (*fmt == 'h' || TOLOWER(*fmt) == 'l' ||
+	    TOLOWER(*fmt) == 'z' || *fmt == 't') {
 		spec->qualifier = *fmt++;
 		if (unlikely(spec->qualifier == *fmt)) {
 			if (spec->qualifier == 'l') {
@@ -1102,7 +1102,7 @@
 			spec->type = FORMAT_TYPE_LONG;
 		else
 			spec->type = FORMAT_TYPE_ULONG;
-	} else if (spec->qualifier == 'Z' || spec->qualifier == 'z') {
+	} else if (TOLOWER(spec->qualifier) == 'z') {
 		spec->type = FORMAT_TYPE_SIZE_T;
 	} else if (spec->qualifier == 't') {
 		spec->type = FORMAT_TYPE_PTRDIFF;
@@ -1249,8 +1249,7 @@
 			if (qualifier == 'l') {
 				long *ip = va_arg(args, long *);
 				*ip = (str - buf);
-			} else if (qualifier == 'Z' ||
-					qualifier == 'z') {
+			} else if (TOLOWER(qualifier) == 'z') {
 				size_t *ip = va_arg(args, size_t *);
 				*ip = (str - buf);
 			} else {
@@ -1540,7 +1539,7 @@
 			void *skip_arg;
 			if (qualifier == 'l')
 				skip_arg = va_arg(args, long *);
-			else if (qualifier == 'Z' || qualifier == 'z')
+			else if (TOLOWER(qualifier) == 'z')
 				skip_arg = va_arg(args, size_t *);
 			else
 				skip_arg = va_arg(args, int *);
@@ -1851,8 +1850,8 @@
 
 		/* get conversion qualifier */
 		qualifier = -1;
-		if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L' ||
-		    *fmt == 'Z' || *fmt == 'z') {
+		if (*fmt == 'h' || TOLOWER(*fmt) == 'l' ||
+		    TOLOWER(*fmt) == 'z') {
 			qualifier = *fmt++;
 			if (unlikely(qualifier == *fmt)) {
 				if (qualifier == 'h') {