b27: poll re-init skip + bits pref-set

docs/sbl-bringup.md

@@ -120,3 +120,8 @@
   в rodata `[0x804B800,0x8058000)` (wild-указатели скипаются), затем
   pop-return (без leak'а, возврат игнорируется). Логгер `0x8034810`
   (`pop.w` 4B) → `b.w S17`. Видимость прогресса вместо счёта инстр.
+
+## b27: poll re-init skip (2026-09-13)
+- Poll-fn `0x8007748`: `cbz r6` (r6=2 константа caller'а, никогда 0) →
+  вечный re-init (`movs r4,#0`, table loop) вместо poll#2-direct.
+  Патч 2B→2B в `b`. Биты 0,1,2 `[0x73A100]` pref-set (scaffold).

qemu/run-sbl.sh

@@ -5,7 +5,7 @@
 set -e
 cd "$(dirname "$0")/.."
 QEMU=~/qemu-src/qemu-8.2.2/build/qemu-system-arm
-B=${1:-b24}
+B=${1:-b27}
 IMG=fw/img/emmc-real.img
 if [ ! -f "$IMG" ]; then
   echo "no $IMG — сначала: python3 tools/ffu_extract.py fw/dl/RM1127_059X5R5_orig.ffu --emmc-user fw/img/user-real.bin"

qemu/saimaa.c

@@ -719,9 +719,10 @@ static void saimaa_machine_init(MachineState *machine)
                 uint32_t v = 0x08006B8D;
                 cpu_physical_memory_write(0x080528D0, &v, 4);
             }
-            /* HW-ready bit (b25): [0x073A100] bit2 (SBL read-only poll). */
+            /* HW-ready bits (b25/b26): [0x073A100] bits 0,1,2 (SBL
+             * read-only polls: bit2 poll#1, bit1 poll#2, bit0 gate). */
             {
-                uint32_t v = 0x00000004;
+                uint32_t v = 0x00000007;
                 cpu_physical_memory_write(0x073A100, &v, 4);
             }
             /* PBL world-switch Thumb-stub (b24, 4B @0x00221EF8):

tools/sbl_patch.py

@@ -1126,6 +1126,95 @@ def main():
 
     save(d, 'img0_b26.elf')
 
+    # b27 = b26 + poll re-init skip (0x8007748 cbz r6 -> b):
+    # r6 (table mode, caller-passed constant 2) never 0, so the poll-fn
+    # re-inits (movs r4,#0) and re-runs its table loop forever instead of
+    # proceeding to poll#2-direct + epilogue. Force direct (2B->2B).
+    # Bits 0,1,2 of [0x73A100] pre-set (scaffold), so polls exit.
+    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'),
+
+        (0x8017AFC, 'bde8fc87', 'eef74fb8'),
+
+        (0x802F690, '9847fee7', 'c046c046'),
+
+        (0x801671C, '9847fee7', 'c046c046'),
+
+        (0x8013BAC, 'f8bd0a4a', 'f3f730b8'),
+
+        (0x801B6BE, 'bde8f081', 'ebf7c3ba'),
+
+        (0x8016720, '10bd0000', 'f0f7b2ba'),
+
+        (0x8034810, 'bde8fc87', 'd2f76eba'),
+
+    ]:
+
+        assert hx(d, va) == exp, (hex(va), hx(d, va))
+
+        set4(d, va, new)
+
+    # Poll re-init skip (b27): cbz r6 (2B 96b1) -> b (2B 14e0).
+    o = off(0x8007748)
+
+    assert d[o:o + 2].hex() == '96b1', hx(d, 0x8007748, 2)
+
+    d[o:o + 2] = bytes.fromhex('14e0')
+
+    # Full bl idiom at 0x8006682 (bl + pop, 6B) -> NOPs (see b18).
+    o = off(0x8006682)
+
+    assert d[o:o + 6].hex() == '00f001f807bd', hx(d, 0x8006682, 6)
+
+    d[o:o + 6] = bytes.fromhex('c046c046c046')
+
+    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')
+
+    # Helper-pop S16 chain (see b25).
+    o = off(0x8007B66)
+
+    assert d[o:o + 2].hex() == '10bd', hx(d, 0x8007B66, 2)
+
+    d[o:o + 2] = bytes.fromhex('6047')
+
+    # Clock S11 (see b24).
+    o = off(0x800E988)
+
+    assert d[o:o + 2].hex() == '10bd', hx(d, 0x800E988, 2)
+
+    d[o:o + 2] = bytes.fromhex('7047')
+
+    save(d, 'img0_b27.elf')
+
 
 
 

tools/sbl_uni.py

@@ -375,10 +375,10 @@ def main():
     # PBL version-table fabrication (b23): [0x080528D0] = STUBV so the
     # rollback query's blx calls maze (returns 0 = versions OK).
     W32(0x080528D0, STUBV)
-    # HW-ready bit fabrication (b25): [0x073A100] bit2 = peripheral
+    # HW-ready bit fabrication (b25): [0x073A100] bits 0,1,2 = peripheral
-    # status done-bit (SBL only reads it, never writes; HW would set it).
+    # status done-bits (poll#1 checks bit2 (lsls#29), poll#2 bit1 (lsls#30),
-    # Poll is lsls#29+bpl (checks bit2, NOT bit31!).
+    # post-poll gate bit0 (lsls#31)). SBL only reads it, never writes.
-    W32(0x073A100, 0x00000004)
+    W32(0x073A100, 0x00000007)
     # PBL world-switch Thumb-stub (b24): the ARM trampoline at 0x221EF8
     # is entered in Thumb (mode confusion at dispatch); real ARM would
     # save regs/CPS to MON and call TZ (not loaded yet). Stub returns 0