diff --git a/scst/include/scst_const.h b/scst/include/scst_const.h
index 11a077f25..54aefe7c1 100644
--- a/scst/include/scst_const.h
+++ b/scst/include/scst_const.h
@@ -303,6 +303,7 @@ static inline int scst_sense_response_code(const uint8_t *sense)
 #define scst_sense_saving_params_unsup		ILLEGAL_REQUEST, 0x39, 0
 #define scst_sense_invalid_message		ILLEGAL_REQUEST, 0x49, 0
 #define scst_sense_parameter_list_length_invalid ILLEGAL_REQUEST, 0x1A, 0
+#define scst_sense_invalid_field_in_command_information_unit ILLEGAL_REQUEST, 0xE, 0x3
 
 /* UNIT_ATTENTION is 6 */
 #define scst_sense_medium_changed_UA		UNIT_ATTENTION,  0x28, 0
diff --git a/scst/src/scst_targ.c b/scst/src/scst_targ.c
index adb3764fb..af1940804 100644
--- a/scst/src/scst_targ.c
+++ b/scst/src/scst_targ.c
@@ -1545,8 +1545,22 @@ static int scst_tgt_pre_exec(struct scst_cmd *cmd)
 					do_zero = true;
 			}
 			if (do_zero) {
-				scst_check_restore_sg_buff(cmd);
-				scst_zero_write_rest(cmd);
+				if ((cmd->write_len & ((1 << cmd->dev->block_shift) - 1)) == 0) {
+					scst_check_restore_sg_buff(cmd);
+					scst_zero_write_rest(cmd);
+				} else {
+					/*
+					 * Looks like it's safer in this case to
+					 * return error instead of zeroing
+					 * the rest to prevent initiators lost
+					 * in 4K and 512 bytes blocks, i.e.
+					 * sending commands on 4K blocks devices
+					 * thinking that they have 512 bytes
+					 * blocks, from corrupting data.
+					 */
+					scst_set_cmd_error(cmd,
+						SCST_LOAD_SENSE(scst_sense_invalid_field_in_command_information_unit));
+				}
 			}
 		}
 	}