diff --git a/stand/ofw/libofw/elf_freebsd.c b/stand/ofw/libofw/elf_freebsd.c
index 80ece7eeba4..9a53300a06c 100644
--- a/stand/ofw/libofw/elf_freebsd.c
+++ b/stand/ofw/libofw/elf_freebsd.c
@@ -91,7 +91,7 @@ __elfN(ofw_exec)(struct preloaded_file *fp)
 		    mdp, sizeof(mdp));
 	} else {
 		OF_chain((void *)reloc, end - (char *)reloc, (void *)entry,
-		    (void *)mdp, sizeof(mdp));
+		    (void *)mdp, 0xfb5d104d);
 	}
 
 	panic("exec returned");
diff --git a/stand/ofw/libofw/ppc64_elf_freebsd.c b/stand/ofw/libofw/ppc64_elf_freebsd.c
index b411da49122..8ac612a9f65 100644
--- a/stand/ofw/libofw/ppc64_elf_freebsd.c
+++ b/stand/ofw/libofw/ppc64_elf_freebsd.c
@@ -93,11 +93,11 @@ ppc64_ofw_elf_exec(struct preloaded_file *fp)
 
 	if (dtbp != 0) {
 		OF_quiesce();
-		((int (*)(u_long, u_long, u_long, void *, u_long))entry)(dtbp, 0, 0,
-		    mdp, sizeof(mdp));
+		((int (*)(u_long, u_long, u_long, void *, u_long))entry)(dtbp,
+		    0, 0, mdp, 0xfb5d104d);
 	} else {
 		OF_chain((void *)reloc, end - (char *)reloc, (void *)entry,
-		    (void *)mdp, sizeof(mdp));
+		    (void *)mdp, 0xfb5d104d);
 	}
 
 	panic("exec returned");
diff --git a/stand/powerpc/kboot/ppc64_elf_freebsd.c b/stand/powerpc/kboot/ppc64_elf_freebsd.c
index 22fa7b57677..1ac0d9eb4b8 100644
--- a/stand/powerpc/kboot/ppc64_elf_freebsd.c
+++ b/stand/powerpc/kboot/ppc64_elf_freebsd.c
@@ -96,7 +96,7 @@ ppc64_elf_exec(struct preloaded_file *fp)
 
 	trampoline[3] = dtb;
 	trampoline[6] = mdp;
-	trampoline[7] = sizeof(mdp);
+	trampoline[7] = 0xfb5d104d;
 	printf("Kernel entry at %#jx (%#x) ...\n", e->e_entry, trampoline[2]);
 	printf("DTB at %#x, mdp at %#x\n", dtb, mdp);
 
diff --git a/stand/powerpc/ps3/ppc64_elf_freebsd.c b/stand/powerpc/ps3/ppc64_elf_freebsd.c
index 3eb991e10ae..2fbb30de117 100644
--- a/stand/powerpc/ps3/ppc64_elf_freebsd.c
+++ b/stand/powerpc/ps3/ppc64_elf_freebsd.c
@@ -89,7 +89,7 @@ ppc64_elf_exec(struct preloaded_file *fp)
 	dev_cleanup();
 
 	entry(0 /* FDT */, 0 /* Phys. mem offset */, 0 /* OF entry */,
-	     (void *)mdp, sizeof(mdp));
+	     (void *)mdp, 0xfb5d104d);
 
 	panic("exec returned");
 }