Index: boot/generic/src/printf_core.c
===================================================================
--- boot/generic/src/printf_core.c	(revision 002fd5f375765c45f5e59bbc374e1418520abddf)
+++ boot/generic/src/printf_core.c	(revision e4c8e3cfcadb1f6ee5b030c72036429781a36a0b)
@@ -101,5 +101,6 @@
 	PrintfQualifierLongLong,
 	PrintfQualifierPointer,
-	PrintfQualifierSize
+	PrintfQualifierSize,
+	PrintfQualifierMax
 } qualifier_t;
 
@@ -643,4 +644,9 @@
 				uc = str_decode(fmt, &nxt, STR_NO_LIMIT);
 				break;
+			case 'j':
+				qualifier = PrintfQualifierMax;
+				i = nxt;
+				uc = str_decode(fmt, &nxt, STR_NO_LIMIT);
+				break;
 			default:
 				/* Default type */
@@ -759,4 +765,8 @@
 				number = (uint64_t) va_arg(ap, size_t);
 				break;
+			case PrintfQualifierMax:
+				size = sizeof(uintmax_t);
+				number = (uint64_t) va_arg(ap, uintmax_t);
+				break;
 			default:
 				/* Unknown qualifier */