diff --git a/source/bforce/prot_binkp.c b/source/bforce/prot_binkp.c
index 694b0c3..0a9e84a 100644
--- a/source/bforce/prot_binkp.c
+++ b/source/bforce/prot_binkp.c
@@ -124,7 +124,7 @@ int binkp_loop(s_binkp_state *bstate) {
             bstate->continuesend = false;
         }
 
-        if (have_to_write==0 && (!no_more_to_send || bstate->extracmd[0]!=-1)) {
+        if (have_to_write==0 && (!no_more_to_send || bstate->extracmd[0]!=(char)-1)) {
             m = binkp_getforsend(bstate, writebuf+BINKP_HEADER, &block_type, &block_length);
             if(m==1 || m==3) {
                 //DEB((D_24554, "got block for sending %d %hu", block_type, block_length));
@@ -340,7 +340,7 @@ int binkp_getforsend(s_binkp_state *bstate, char *buf, int *block_type, unsigned
 {
     int my_sf, wr_pos;
     int n; // read file
-    if (bstate->extracmd[0]!=-1) {
+    if (bstate->extracmd[0]!=(char)-1) {
         DEB((D_24554, "Send cmd to remote %d %s", bstate->extracmd[0], bstate->extracmd+1));
         buf[0] = bstate->extracmd[0];
         strcpy(buf+1, bstate->extracmd+1);
@@ -954,7 +954,7 @@ case BPMSG_GET:              /* Get a file from offset */
             }
             DEB((D_24554, "M_GET file %s size %d time %d offset %d", getfi.fn, getfi.sz, getfi.tm, getfi.offs));
 
-            if (bstate->extracmd[0] != -1) return 0;
+            if (bstate->extracmd[0] != (char)-1) return 0;
 
             if (bstate->pi->send) if (p_compfinfo(bstate->pi->send, getfi.fn, getfi.sz, getfi.tm)==0) {
                 DEB((D_24554, "M_GET for currently transmitted file"));
@@ -1044,7 +1044,7 @@ case BINKP_BLK_DATA:
             return 1;
         }
 
-        if (bstate->extracmd[0] != -1) return 0;
+        if (bstate->extracmd[0] != (char)-1) return 0;
 
         long int n;
         n = p_rx_writefile(buf, block_length, bstate->pi);