bootm: improve error message when gzip decompression buffer is too small

Currently, when decompressing a gzip-compressed image during bootm, a
generic error such as "inflate() returned -5" is shown when the buffer is
too small. However, it is not immediately clear that this is caused by
CONFIG_SYS_BOOTM_LEN being too small.

This patch improves error handling by:
- Detecting Z_BUF_ERROR (-5) returned from the inflate() call
- Suggesting the user to increase CONFIG_SYS_BOOTM_LEN when applicable
- Preserving the original return code from zunzip() instead of overwriting
  it with -1

By providing clearer hints when decompression fails due to insufficient
buffer size, this change helps users diagnose and fix boot failures more
easily.

Signed-off-by: Aristo Chen <[email protected]>
Reviewed-by: Tom Rini <[email protected]>
Reviewed-by: Mattijs Korpershoek <[email protected]>

1 files changed, 1 insertions, 1 deletions

diff --git a/lib/gunzip.c b/lib/gunzip.c
index 52007715bda..a05dcde9a75 100644
--- a/lib/gunzip.c
+++ b/lib/gunzip.c
@@ -299,7 +299,7 @@ __rcode int zunzip(void *dst, int dstlen, unsigned char *src,
 		if (stoponerr == 1 && r != Z_STREAM_END &&
 		    (s.avail_in == 0 || s.avail_out == 0 || r != Z_BUF_ERROR)) {
 			printf("Error: inflate() returned %d\n", r);
-			err = -1;
+			err = r;
 			break;
 		}
 	} while (r == Z_BUF_ERROR);