diff --git a/main.S b/main.S
index eedac97..ac4441d 100755
--- a/main.S
+++ b/main.S
@@ -26,7 +26,7 @@ _start:
 
 //copy U-Boot to head of RAM 
     ldr r3, =0x37500000 //copy start
-    ldr r1, =0x37540000 //copy end
+    add r1, r3, r0 //copy end
     copy_loop:
     mov r2, r3
     sub r3, r3, #0x7500000 //copy distination
@@ -34,7 +34,7 @@ _start:
     cmp r2, r1
     str r0, [r3]
     mov r3, r2
-    bne copy_loop
+    blt copy_loop
 
 //RAM clear
     ldr r2,=0x60200000 //clear start