diff --git a/libr/core/cmd_write.inc.c b/libr/core/cmd_write.inc.c
index abfa0d0c27581..09988b37a1a3b 100644
--- a/libr/core/cmd_write.inc.c
+++ b/libr/core/cmd_write.inc.c
@@ -2165,10 +2165,11 @@ static int cmd_wb(void *data, const char *input) {
 	if (uil > 8) {
 		R_LOG_ERROR ("wb only operates on bytes");
 	} else if (uil > 0) {
-		int shift = 8 - uil;
-		b <<= shift;
-		b >>= shift;
-		b |= (n << shift);
+		// Shift left and right to zero uil most significant bits
+		b <<= uil;
+		b >>= uil;
+		// Overwrite uil most significant bits and keep the rest
+		b |= (n << (8 - uil));
 		r_io_write_at (core->io, core->offset, &b, 1);
 	} else {
 		r_core_cmd_help_match (core, help_msg_w, "wb");
diff --git a/test/db/cmd/cmd_print_bitformat b/test/db/cmd/cmd_print_bitformat
index be8005990a514..6868779f48d6a 100644
--- a/test/db/cmd/cmd_print_bitformat
+++ b/test/db/cmd/cmd_print_bitformat
@@ -56,7 +56,38 @@ EXPECT=<<EOF
 00000000
 11000000
 00010000
-10110010
+10100010
 EOF
 RUN
 
+NAME=pbwb least significant bit
+FILE=-
+CMDS=<<EOF
+pb 8
+wb 00000001
+pb 8
+wb 00000000
+pb 8
+EOF
+EXPECT=<<EOF
+00000000
+00000001
+00000000
+EOF
+RUN
+
+NAME=pbwb most significant bit
+FILE=-
+CMDS=<<EOF
+pb 8
+wb 11111111
+pb 8
+wb 0
+pb 8
+EOF
+EXPECT=<<EOF
+00000000
+11111111
+01111111
+EOF
+RUN