diff --git a/mysql-test/r/csv.result b/mysql-test/r/csv.result
index 34dc1cb5b2e..f7a4d0c2217 100644
--- a/mysql-test/r/csv.result
+++ b/mysql-test/r/csv.result
@@ -5261,3 +5261,11 @@ CREATE TABLE `bug21328` (
 insert into bug21328 values (1,NULL,NULL);
 alter table bug21328 engine=myisam;
 drop table bug21328;
+create table t1(a blob, b int) engine=csv;
+insert into t1 values('a', 1);
+flush tables;
+update t1 set b=2;
+select * from t1;
+a	b
+a	2
+drop table t1;
diff --git a/mysql-test/t/csv.test b/mysql-test/t/csv.test
index c7c7f3e13ab..f353b38ba67 100644
--- a/mysql-test/t/csv.test
+++ b/mysql-test/t/csv.test
@@ -1674,3 +1674,14 @@ CREATE TABLE `bug21328` (
 insert into bug21328 values (1,NULL,NULL);
 alter table bug21328 engine=myisam;
 drop table bug21328;
+
+#
+# BUG#28971 - ALTER TABLE followed by UPDATE for a CSV table make server
+# crash
+#
+create table t1(a blob, b int) engine=csv;
+insert into t1 values('a', 1);
+flush tables;
+update t1 set b=2;
+select * from t1;
+drop table t1;
diff --git a/storage/csv/ha_tina.cc b/storage/csv/ha_tina.cc
index 6de153c82d7..e503f639d58 100644
--- a/storage/csv/ha_tina.cc
+++ b/storage/csv/ha_tina.cc
@@ -590,6 +590,7 @@ int ha_tina::find_current_row(uchar *buf)
   int eoln_len;
   my_bitmap_map *org_bitmap;
   int error;
+  bool read_all;
   DBUG_ENTER("ha_tina::find_current_row");
 
   /*
@@ -601,6 +602,8 @@ int ha_tina::find_current_row(uchar *buf)
                        local_saved_data_file_length, &eoln_len)) == 0)
     DBUG_RETURN(HA_ERR_END_OF_FILE);
 
+  /* We must read all columns in case a table is opened for update */
+  read_all= !bitmap_is_clear_all(table->write_set);
   /* Avoid asserts in ::store() for columns that are not going to be updated */
   org_bitmap= dbug_tmp_use_all_columns(table, table->write_set);
   error= HA_ERR_CRASHED_ON_USAGE;
@@ -678,7 +681,7 @@ int ha_tina::find_current_row(uchar *buf)
       goto err;
     }
 
-    if (bitmap_is_set(table->read_set, (*field)->field_index))
+    if (read_all || bitmap_is_set(table->read_set, (*field)->field_index))
       (*field)->store(buffer.ptr(), buffer.length(), buffer.charset());
   }
   next_position= end_offset + eoln_len;