sbl b17: NOP banner call (stub tail heap-clobbered)

tools/sbl_patch.py

@@ -230,6 +230,33 @@ def main():
     assert d[o:o + 4].hex() == '07f026be', hx(d, 0x8013AA8)
     d[o:o + 4] = bytes.fromhex('c046c046')
     save(d, 'img0_b13.elf')
+    # b17 = b16 with banner call NOPed (blx r3 + b.n self -> NOP NOP):
+    # logger is non-essential; banner stub tail gets heap-clobbered and
+    # the 4B bl return lands mid-insn. Fall through to 0x802f694.
+    d = bytearray(base)
+    for va, (a, b) in BLX2BL.items():
+        set4(d, va, b)
+    for va, exp, new in [
+        (0x802F664, 'e4f77efc', 'c046c046'),
+        (0x802F672, 'e6f7bbfa', 'c046c046'),
+        (0x802F678, 'e9f7fef9', 'c046c046'),
+        (0x801B71E, '9847fee7', 'c046c046'),
+        (0x8008396, 'fef780f9', 'c046c046'),
+        (0x8016184, 'fdf790fc', 'c046c046'),
+        (0x801B76C, '280b0508', '00000708'),
+        (0x8006684, '01f807bd', '46c046c0'),
+        (0x8017AFC, 'bde8fc87', 'e8f3b0b2'),
+        (0x802F690, '9847fee7', 'c046c046'),
+    ]:
+        assert hx(d, va) == exp, (hex(va), hx(d, va))
+        set4(d, va, new)
+    o = off(0x8013AA8)
+    assert d[o:o + 4].hex() == '07f026be', hx(d, 0x8013AA8)
+    d[o:o + 4] = bytes.fromhex('c046c046')
+    o = off(0x8013BA6)
+    assert d[o:o + 2].hex() == 'b888', (hex(0x8013BA6), hx(d, 0x8013BA6, 2))
+    d[o:o + 2] = bytes.fromhex('ff20')
+    save(d, 'img0_b17.elf')
 
 
 if __name__ == '__main__':