From e473826732585900411dced1c26fb0375c904b9c Mon Sep 17 00:00:00 2001
From: SashegDev <gdsasheg@gmail.com>
Date: Fri, 11 Sep 2026 07:15:31 +0000
Subject: [PATCH] banner stub: preserve lr, pop-return to caller

---
 qemu/banner.S |  8 +++++---
 qemu/saimaa.c | 14 +++++---------
 2 files changed, 10 insertions(+), 12 deletions(-)

diff --git a/qemu/banner.S b/qemu/banner.S
index ba49f24..1e35ea4 100644
--- a/qemu/banner.S
+++ b/qemu/banner.S
@@ -1,11 +1,13 @@
     .syntax unified
     .cpu cortex-a7
     .thumb
-    @ Banner stub for SBL1 logger call at 0x802f690 (blx r3 patched to bl here).
-    @ r0 = string. Print raw bytes via UARTDM until NUL (cap 256), return 0.
+    @ Banner stub for SBL1 logger call at 0x802f690 (patched to bl here).
+    @ r0 = string. Print raw bytes via UARTDM until NUL (cap 256).
+    @ Preserve lr (set by bl) and return to caller with r0=0.
     .text
     .global banner_stub
 banner_stub:
+    push {r4, lr}
     movw r3, #0xf000
     movt r3, #0x78a
 bn_loop:
@@ -15,4 +17,4 @@ bn_loop:
     b bn_loop
 bn_done:
     movs r0, #0
-    bx lr
+    pop {r4, pc}
diff --git a/qemu/saimaa.c b/qemu/saimaa.c
index 767c295..0cc1009 100644
--- a/qemu/saimaa.c
+++ b/qemu/saimaa.c
@@ -440,17 +440,13 @@ static void saimaa_machine_init(MachineState *machine)
                 }
             }
             /* Banner stub at 0x08062150: print r0 string via UARTDM
-             * (b16 redirects 0x802f690 blx here). Built from qemu/banner.S */
+             * (b16 redirects 0x802f690 blx here). Built from qemu/banner.S:
+             * push/pop frame, preserves lr, returns r0=0 to caller. */
             {
                 static const uint8_t bn[] = {
-                    0x4f, 0xf2, 0x00, 0x03, /* movw r3,#0xf000 */
-                    0xc0, 0xf2, 0x8a, 0x73, /* movt r3,#0x78a */
-                    0x10, 0xf8, 0x01, 0x1b, /* ldrb r1,[r0],#1 */
-                    0x09, 0xb1,             /* cbz r1,done */
-                    0x19, 0x67,             /* str r1,[r3,#0x70] */
-                    0xfa, 0xe7,             /* b loop */
-                    0x00, 0x20,             /* movs r0,#0 */
-                    0x70, 0x47,             /* bx lr */
+                    0x10, 0xb5, 0x4f, 0xf2, 0x00, 0x03, 0xc0, 0xf2,
+                    0x8a, 0x73, 0x10, 0xf8, 0x01, 0x1b, 0x09, 0xb1,
+                    0x19, 0x67, 0xfa, 0xe7, 0x00, 0x20, 0x10, 0xbd,
                 };
                 size_t k;
                 for (k = 0; k < sizeof(bn); k += 4) {