sbl b14: S6 pop redirected to stublet 0x8062140 (was null-sled)

2026-09-11 06:29:06 +00:00
parent 61a0b724ff
commit 22b259e818
3 changed files with 52 additions and 0 deletions
@@ -133,6 +133,28 @@ def main():
    assert d[o:o + 4].hex() == '07f026be', hx(d, 0x8013AA8)
    d[o:o + 4] = bytes.fromhex('c046c046')
    save(d, 'img0_b12.elf')
+    # b14 = b13 + redirect S6 pop (0x8017afc ldmia.w sp!,{r2-r9,sl,pc})
+    # to S6 stublet at 0x08062140 (pc slot clobbered to 0 at runtime)
+    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, 'e8bd87fc', '4af020bb'),
+    ]:
+        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')
+    save(d, 'img0_b14.elf')
    # b13 = b12 + NOP strb.w fp,[r1,#-7]! at 0x8006684 (helper stores
    # fp into struct r1, but r1 arrives NULL from 0x8007e82 chain;
    # store to [0-7]=0xfffffff9 faults; struct unrecoverable here)