diff --git a/libr/core/cio.c b/libr/core/cio.c
index 3a8f358f21..8299788ac6 100644
--- a/libr/core/cio.c
+++ b/libr/core/cio.c
@@ -141,15 +141,22 @@ R_API ut8* r_core_transform_op(RCore *core, const char *arg, char op) {
 	int i, j;
 	ut64 len;
 	char *str = NULL;
-	ut8 *buf;
-
-	buf = (ut8 *)malloc (core->blocksize);
+	ut8 *buf = (ut8 *)malloc (core->blocksize);
 	if (!buf) {
 		return NULL;
 	}
+	if (op == 'i') { // "woi"
+		int hbs = core->blocksize / 2;
+		int j = core->blocksize - 1;
+		for (i = 0; i < hbs; i++, j--) {
+			buf[i] = core->block[j];
+			buf[j] = core->block[i];
+		}
+		return buf;
+	}
 	memcpy (buf, core->block, core->blocksize);
 
-	if (op!='e') {
+	if (op != 'e') {
 		// fill key buffer either from arg or from clipboard
 		if (arg) {  // parse arg for key
 			// r_hex_str2bin() is guaranteed to output maximum half the
@@ -177,7 +184,7 @@ R_API ut8* r_core_transform_op(RCore *core, const char *arg, char op) {
 	}
 
 	// execute the operand
-	if (op=='e') {
+	if (op == 'e') {
 		int wordsize = 1;
 		char *os, *p, *s = strdup (arg);
 		int n = 0, from = 0, to = UT8_MAX, dif = 0, step = 1;
@@ -312,7 +319,7 @@ beach:
 }
 
 R_API int r_core_write_op(RCore *core, const char *arg, char op) {
-	ut8 *buf = r_core_transform_op(core, arg, op);
+	ut8 *buf = r_core_transform_op (core, arg, op);
 	if (!buf) {
 		return false;
 	}
diff --git a/libr/core/cmd_write.c b/libr/core/cmd_write.c
index a0148a1989..5ada301a4f 100644
--- a/libr/core/cmd_write.c
+++ b/libr/core/cmd_write.c
@@ -101,6 +101,7 @@ static const char *help_msg_wo[] = {
 	"woD","[algo] [key] [IV]","decrypt current block with given algo and key",
 	"woe"," [from to] [step] [wsz=1]","..  create sequence",
 	"woE"," [algo] [key] [IV]", "encrypt current block with given algo and key",
+	"woi","", "inverse bytes in current block",
 	"wol"," [val]","<<= shift left",
 	"wom"," [val]", "*=  multiply",
 	"woo"," [val]","|=  or",
@@ -311,27 +312,28 @@ static int wo_handler_old(void *data, const char *input) {
 	int len;
 	int value;
 	switch (input[0]) {
-	case 'e':
+	case 'e': // "woe"
 		if (input[1]!=' ') {
 			r_cons_printf ("Usage: 'woe from-to step'\n");
 			return -1;
 		}
 		/* fallthru */
-	case 'a':
-	case 's':
-	case 'A':
-	case 'x':
-	case 'r':
-	case 'l':
-	case 'm':
-	case 'd':
-	case 'o':
-	case 'w':
+	case 'a': // "woa"
+	case 's': // "wos"
+	case 'A': // "woA"
+	case 'x': // "wox"
+	case 'r': // "wor"
+	case 'l': // "wol"
+	case 'm': // "wom"
+	case 'i': // "woi"
+	case 'd': // "wod"
+	case 'o': // "woo"
+	case 'w': // "wow"
 	case '2': // "wo2"
 	case '4': // "wo4"
 	case '8': // "wo8"
 		if (input[1]) {  // parse val from arg
-			r_core_write_op (core, input + 2, input[0]);
+			r_core_write_op (core, r_str_trim_head_ro (input + 2), input[0]);
 		} else {  // use clipboard instead of val
 			r_core_write_op (core, NULL, input[0]);
 		}