On Tuesday 26 October 2021 16:21:02 Stefan Roese wrote:
> On 26.10.21 14:40, Pali Rohár wrote:
> > My another guess there could be a problem is usage of stack. Maybe it is
> > possible that register with stack pointer is not initialized after the
> > full transfer when going to execute main image. Same arm baudrate change
> > code is used after the SPL and before main U-Boot, and the first
> > instruction is "push". Maybe modifying the arm code to not use stack
> > when switching the baudrate back to 115200 could also help. I will look
> > at it.
> 
> Thanks.

Here is dirty hack patch which completely disable calling code for
changing baudrate back to 115200 on ARM side:

diff --git a/tools/kwboot.c b/tools/kwboot.c
index 5f4ff673972e..00d58a239c71 100644
--- a/tools/kwboot.c
+++ b/tools/kwboot.c
@@ -1070,17 +1070,17 @@ kwboot_xmodem(int tty, const void *_img, size_t size, 
int baudrate)
                return rc;
 
        if (baudrate) {
-               char buf[sizeof(kwb_baud_magic)];
-
-               kwboot_printv("Waiting 1s for baudrate change magic\n");
-               rc = kwboot_tty_recv(tty, buf, sizeof(buf), 1000);
-               if (rc)
-                       return rc;
-
-               if (memcmp(buf, kwb_baud_magic, sizeof(buf))) {
-                       errno = EPROTO;
-                       return -1;
-               }
+//             char buf[sizeof(kwb_baud_magic)];
+//
+//             kwboot_printv("Waiting 1s for baudrate change magic\n");
+//             rc = kwboot_tty_recv(tty, buf, sizeof(buf), 1000);
+//             if (rc)
+//                     return rc;
+//
+//             if (memcmp(buf, kwb_baud_magic, sizeof(buf))) {
+//                     errno = EPROTO;
+//                     return -1;
+//             }
 
                kwboot_printv("\nChanging baudrate back to 115200 Bd\n\n");
                rc = kwboot_tty_change_baudrate(tty, 115200);
@@ -1551,8 +1551,8 @@ kwboot_img_patch(void *img, size_t *size, int baudrate)
                 * This code is appended after the data part of the image and
                 * execaddr is changed to execute this code before U-Boot 
proper.
                 */
-               kwboot_printv("Injecting code for changing baudrate back\n");
-               _copy_baudrate_change_code(hdr, size, 1, baudrate, 115200);
+//             kwboot_printv("Injecting code for changing baudrate back\n");
+//             _copy_baudrate_change_code(hdr, size, 1, baudrate, 115200);
 
                /* recompute header size */
                hdrsz = kwbheader_size(hdr);

As main U-Boot binary on ARM resets UART, it means that baudrate is
properly set to 115200. Probably beginning of the U-Boot output could be
lost but at least console should start.

Could you try this patch if it starts working now?

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