From 511d0b36eda956d9c8388238de213092dee8e2de Mon Sep 17 00:00:00 2001
From: kicer <kicer@foresh.com>
Date: Thu, 18 Dec 2025 10:43:47 +0800
Subject: [PATCH] bootloader: reset X before wait

---
 scripts/bootloader.opt | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/scripts/bootloader.opt b/scripts/bootloader.opt
index bc39121..20d6729 100644
--- a/scripts/bootloader.opt
+++ b/scripts/bootloader.opt
@@ -1,15 +1,16 @@
 ;; M Code
 ;;    option   O0 O1 N1 O2 N2 O3 N3 O4     N4 O5 N5
-;;      4800   00 00 FF 00 FF 00 FF 00     FF 00 FF -- -- -- -- --
-;; 03D0|4810   -- -- -- -- -- -- -- --     -- -- -- -- 00 03 DF A6
-;; 03E0|4820   0D C7 52 32 C7 52 35 C7     52 31 5C 27 0D 72 0B 52
-;; 03F0|4830   30 F8 3B 52 31 5F 4C 26     F1 81 72 CC 48 3E 80 04
+;;      4800   00 00 ff 00 ff 00 ff 00     ff 00 ff -- -- -- -- --
+;; 03D0|4810   -- -- -- -- -- -- -- --     -- -- -- -- 00 03 df a6
+;; 03E0|4820   0d c7 52 32 c7 52 35 c7     52 31 5f 5c 27 0c 72 0b
+;; 03F0|4830   52 30 f8 3b 52 31 4c 26     f1 81 72 cc 48 3e 80 04
 
-;; UART1 register address definitions (STM8S103F3)
+;; UART1 register address definitions
 UART1_SR    = 0x5230   ; Status register
 UART1_DR    = 0x5231   ; Data register
 UART1_BRR1  = 0x5232   ; Baud rate register 1
 UART1_CR2   = 0x5235   ; Control register 2
+
 RAM_SIZE    = 0x0400   ; Ram size (end of address)
 
 ;; Bootloader body (located in OPT reserved area 0x481C-0x483F)
@@ -34,15 +35,16 @@ _bootO_start:
 
     ;; Receive maximum 243-byte data block and push onto stack
 _bootO_rx_byte:
+    clrw    X          ; [5F] Reset X (for timeout detection)
+_bootO_rx_wait:
     incw    X           ; [5C] Increment X, check for overflow (timeout detection)
-    jreq    _bootO_exit ; [27 0D] If X overflows (receive timeout), exit
+    jreq    _bootO_exit ; [27 0C] If X overflows (receive timeout), exit
 
     ;; Wait for data reception
-    btjf    UART1_SR, #5, _bootO_rx_byte ;[72 0B 52 30 F8]
+    btjf    UART1_SR, #5, _bootO_rx_wait;[72 0B 52 30 F8]
 
     ;; Data received, push onto stack
     push    UART1_DR   ; [3B 52 31]
-    clrw    X          ; [5F] Reset X (for timeout detection)
     inc     A          ; [4C] Increment A, used as receive counter
     jrne    _bootO_rx_byte ; [26 F1] If A is not 0, continue receiving