diff --git a/jtag/src/cmd/bit.c b/jtag/src/cmd/bit.c
index 6cff8ffc..3a5be906 100644
--- a/jtag/src/cmd/bit.c
+++ b/jtag/src/cmd/bit.c
@@ -31,6 +31,18 @@
 
 #include "cmd.h"
 
+static void
+cmd_bit_print_params( char *params[], unsigned int parameters, char *command )
+{
+	unsigned int i;
+
+	strcpy(command, params[0]);
+	for (i=1; i<parameters; i++) {
+		strcat(command, " ");
+		strcat(command, params[i]);
+	}
+}
+
 static int
 cmd_bit_run( char *params[] )
 {
@@ -40,13 +52,20 @@ cmd_bit_run( char *params[] )
 	int type;
 	int safe;
 	unsigned int control;
+	unsigned int parameters = cmd_params( params );
+	char command[1024];
 
-	if ((cmd_params( params ) != 5) && (cmd_params( params ) != 8))
-		return -1;
+	cmd_bit_print_params(params, parameters, command);
 
+	if ((parameters != 5) && (parameters != 8)) {
+		printf( _("%s: invalid number of parameters (%d) for command '%s'\n"), "bit", parameters, command );
+		return -1;
+	}
 
-	if (!cmd_test_cable())
+	if (!cmd_test_cable()) {
+		printf( _("%s: cable test failed for command '%s'\n"), "bit", command);
 		return 1;
+	}
 
 	if (!chain->parts) {
 		printf( _("Run \"detect\" first.\n") );
@@ -61,26 +80,30 @@ cmd_bit_run( char *params[] )
 	part = chain->parts->parts[chain->active_part];
 	bsr = part_find_data_register( part, "BSR" );
 	if (bsr == NULL) {
-		printf( _("missing Boundary Scan Register (BSR)\n") );
+		printf( _("%s: missing Boundary Scan Register (BSR) for command '%s'\n"), "bit", command );
 		return 1;
 	}
 
 	/* bit number */
-	if (cmd_get_number( params[1], &bit ))
+	if (cmd_get_number( params[1], &bit )) {
+		printf( _("%s: unable to get boundary bit number for command '%s'\n"), "bit", command );
 		return -1;
+	}
 
 	if (bit >= bsr->in->len) {
-		printf( _("invalid boundary bit number\n") );
+		printf( _("%s: invalid boundary bit number for command '%s'\n"), "bit", command );
 		return 1;
 	}
 	if (part->bsbits[bit] != NULL) {
-		printf( _("duplicate bit declaration\n") );
+		printf( _("%s: duplicate bit declaration for command '%s'\n"), "bit", command );
 		return 1;
 	}
 
 	/* bit type */
-	if (strlen( params[2] ) != 1)
+	if (strlen( params[2] ) != 1) {
+		printf( _("%s: invalid bit type length for command '%s'\n"), "bit", command );
 		return -1;
+	}
 	switch (params[2][0]) {
 	    case 'I':
 	    case 'i':
@@ -103,20 +126,23 @@ cmd_bit_run( char *params[] )
 			type = BSBIT_INTERNAL;
 			break;
 		default:
+			printf( _("%s: invalid bit type for command '%s'\n"), "bit", command );
 			return -1;
 	}
 
 	/* default (safe) value */
-	if (strlen( params[3] ) != 1)
+	if (strlen( params[3] ) != 1) {
+		printf( _("%s: invalid default value length for command '%s'\n"), "bit", command );
 		return -1;
+	}
 
 	safe = (params[3][0] == '1') ? 1 : 0;
 	bsr->in->data[bit] = safe;
 
 	/* allocate bsbit */
-	part->bsbits[bit] = bsbit_alloc( bit, params[4], type, part_find_signal( part, params[4] ), safe );
+	part->bsbits[bit] = bsbit_alloc( bit, params[4], type, part->signals, safe );
 	if (part->bsbits[bit] == NULL) {
-		printf( _("out of memory\n") );
+		printf( _("%s: out of memory for command '%s'\n"), "bit", command );
 		return 1;
 	}
 
@@ -125,22 +151,27 @@ cmd_bit_run( char *params[] )
 		return 1;
 
 	/* control bit number */
-	if (cmd_get_number( params[5], &control ))
+	if (cmd_get_number( params[5], &control )) {
+		printf( _("%s: unable to get control bit number for command '%s'\n"), "bit", command );
 		return -1;
+	}
 	if (control >= bsr->in->len) {
-		printf( _("invalid control bit number\n") );
+		printf( _("%s: invalid control bit number for command '%s'\n"), "bit", command );
 		return 1;
 	}
 	part->bsbits[bit]->control = control;
 
 	/* control value */
-	if (strlen( params[6] ) != 1)
+	if (strlen( params[6] ) != 1) {
+		printf( _("%s: invalid control value length for command '%s'\n"), "bit", command );
 		return -1;
+	}
 	part->bsbits[bit]->control_value = (params[6][0] == '1') ? 1 : 0;
 
 	/* control state */
 	if (strcasecmp(params[7], "Z"))
 		return -1;
+	}
 	part->bsbits[bit]->control_state = BSBIT_STATE_Z;
 
 	return 1;