Author: Stefan Achatz
https://sourceforge.net/p/hptalx/patches/4/

--- a/src/kermit.c
+++ b/src/kermit.c
@@ -52,6 +52,7 @@
 #include <pty.h>
 #include <termios.h>
 #include <signal.h>
+#include <errno.h>
 
 /*
  * Global variable that holds the last Kermit status 
@@ -297,44 +298,22 @@ k_wait_ready (char **o, size_t * size)
 		 * has arrived 
 		 */
 		if (br > 0) {
-			if (*size == 0) {
-				/*
-				 * First time we read into *o 
-				 */
-				*o = (char *) malloc (br);
-				if (*o == NULL) {
-					return k_errno = K_MALLOC;
-				}
-
-				/*
-				 * Zero out everthing in *o
-				 */
-				memset ((void *) *o, 0, br);
-				memcpy ((void *) *o, (void *) buff, br);
-				*size = br;
+
+			*size += br;
+			
+			if (*size == br) {
+				*o = (char *) malloc (*size);
 			} else {
-				/*
-				 * Previous reads took place 
-				 */
-
-				/*
-				 * New size of *o 
-				 */
-				*size += br;
 				*o = (char *) realloc (*o, *size);
+			}
+			
+			if (*o == NULL) {
+				return k_errno = K_MALLOC;
+			}
 
-				if (*o == NULL) {
-					return k_errno = K_MALLOC;
-				}
+			memcpy ((void *) (*o + (*size - br)), (void *) buff, br);
 
-				memset ((void *) (*o + (*size - br)), 0, br);
-				/*
-				 * Copy content from buff to *o
-				 * at old pos in *o -> (size-br) 
-				 */
-				memcpy ((void *) (*o + (*size - br)), (void *) buff, br);
-			}
-		} else {
+		} else if (br == 0 || errno == EAGAIN) {
 			/*
 			 * Wait nicely for new data
 			 */
@@ -343,6 +322,8 @@ k_wait_ready (char **o, size_t * size)
 				return k_errno = K_TIMEOUT;
 			}
 
+		} else {
+			return k_errno = K_READ;
 		}
 
 		/*
@@ -352,7 +333,7 @@ k_wait_ready (char **o, size_t * size)
 		tv.tv_usec = 0;
 
 	}
-	while ((strstr (*o, K_KERMIT_PROMPT) == NULL)
+	while ((*o != 0 && strstr (*o, K_KERMIT_PROMPT) == NULL)
 		   || (select (FD_SETSIZE, &rset, NULL, NULL, &tv) != 0));
 	return k_errno = K_OK;
 }