Index: boot/generic/src/printf_core.c
===================================================================
--- boot/generic/src/printf_core.c	(revision a2da43ce0270f2b1188a5e2ba61783c8c4e3bb13)
+++ boot/generic/src/printf_core.c	(revision bf61d3ad9628d50dbbbcc790b6e57d85ff739092)
@@ -79,5 +79,6 @@
 	PrintfQualifierLong,
 	PrintfQualifierLongLong,
-	PrintfQualifierPointer
+	PrintfQualifierPointer,
+	PrintfQualifierSize
 } qualifier_t;
 
@@ -431,6 +432,4 @@
  *  - ""   Signed or unsigned int (default value).@n
  *  - "l"  Signed or unsigned long int.@n
- *         If conversion is "c", the character is wchar_t (wide character).@n
- *         If conversion is "s", the string is wchar_t * (wide string).@n
  *  - "ll" Signed or unsigned long long int.@n
  *
@@ -612,4 +611,9 @@
 				}
 				break;
+			case 'z':
+				qualifier = PrintfQualifierSize;
+				i = nxt;
+				uc = str_decode(fmt, &nxt, STR_NO_LIMIT);
+				break;
 			default:
 				/* Default type */
@@ -720,4 +724,8 @@
 				number = (uint64_t) (uintptr_t) va_arg(ap, void *);
 				break;
+			case PrintfQualifierSize:
+				size = sizeof(size_t);
+				number = (uint64_t) va_arg(ap, size_t);
+				break;
 			default:
 				/* Unknown qualifier */