Index: head/sys/boot/uboot/common/main.c
===================================================================
--- head/sys/boot/uboot/common/main.c
+++ head/sys/boot/uboot/common/main.c
@@ -387,7 +387,7 @@
 }
 
 int
-main(void)
+main(int argc, char **argv)
 {
 	struct api_signature *sig = NULL;
 	int load_type, load_unit, load_slice, load_partition;
@@ -395,12 +395,15 @@
 	const char *ldev;
 
 	/*
+	 * We first check if a command line argument was passed to us containing
+	 * API's signature address. If it wasn't then we try to search for the
+	 * API signature via the usual hinted address.
 	 * If we can't find the magic signature and related info, exit with a
 	 * unique error code that U-Boot reports as "## Application terminated,
 	 * rc = 0xnnbadab1". Hopefully 'badab1' looks enough like "bad api" to
 	 * provide a clue. It's better than 0xffffffff anyway.
 	 */
-	if (!api_search_sig(&sig))
+	if (!api_parse_cmdline_sig(argc, argv, &sig) && !api_search_sig(&sig))
 		return (0x01badab1);
 
 	syscall_ptr = sig->syscall;
Index: head/sys/boot/uboot/lib/glue.h
===================================================================
--- head/sys/boot/uboot/lib/glue.h
+++ head/sys/boot/uboot/lib/glue.h
@@ -58,6 +58,7 @@
 int syscall(int, int *, ...);
 void *syscall_ptr;
 
+int api_parse_cmdline_sig(int argc, char **argv, struct api_signature **sig);
 int api_search_sig(struct api_signature **sig);
 
 #define	UB_MAX_MR	16		/* max mem regions number */
Index: head/sys/boot/uboot/lib/glue.c
===================================================================
--- head/sys/boot/uboot/lib/glue.c
+++ head/sys/boot/uboot/lib/glue.c
@@ -68,6 +68,41 @@
 }
 
 /*
+ * Checks to see if API signature's address was given to us as a command line
+ * argument by U-Boot.
+ *
+ * returns 1/0 depending on found/not found result
+ */
+int
+api_parse_cmdline_sig(int argc, char **argv, struct api_signature **sig)
+{
+	unsigned long api_address;
+	int c;
+
+	api_address = 0;
+	opterr = 0;
+	optreset = 1;
+	optind = 1;
+
+	while ((c = getopt (argc, argv, "a:")) != -1)
+		switch (c) {
+		case 'a':
+			api_address = strtoul(optarg, NULL, 16);
+			break;
+		default:
+			break;
+		}
+
+	if (api_address != 0) {
+		*sig = (struct api_signature *)api_address;
+		if (valid_sig(*sig))
+			return (1);
+	}
+
+	return (0);
+}
+
+/*
  * Searches for the U-Boot API signature
  *
  * returns 1/0 depending on found/not found result