diff --git a/apps/plugins/viewer.c b/apps/plugins/viewer.c
old mode 100644
new mode 100755
index f01afbb..ea3f6c7
--- a/apps/plugins/viewer.c
+++ b/apps/plugins/viewer.c
@@ -32,12 +32,12 @@ PLUGIN_HEADER
 #define WRAP_TRIM          44  /* Max number of spaces to trim (arbitrary) */
 #define MAX_COLUMNS        64  /* Max displayable string len (over-estimate) */
 #define MAX_WIDTH         910  /* Max line length in WIDE mode */
-#define READ_PREV_ZONE    910  /* Arbitrary number less than SMALL_BLOCK_SIZE */
-#define SMALL_BLOCK_SIZE  0x1000 /* 4k: Smallest file chunk we will read */
-#define LARGE_BLOCK_SIZE  0x2000 /* 8k: Preferable size of file chunk to read */
+#define READ_PREV_ZONE    (block_size*9/10)  /* Arbitrary number less than SMALL_BLOCK_SIZE */
+#define SMALL_BLOCK_SIZE  block_size /* 4k: Smallest file chunk we will read */
+#define LARGE_BLOCK_SIZE  (block_size << 1) /* 8k: Preferable size of file chunk to read */
 #define TOP_SECTOR     buffer
 #define MID_SECTOR     (buffer + SMALL_BLOCK_SIZE)
-#define BOTTOM_SECTOR  (buffer + 2*(SMALL_BLOCK_SIZE))
+#define BOTTOM_SECTOR  (buffer + (SMALL_BLOCK_SIZE << 1))
 #define SCROLLBAR_WIDTH     6
 
 #define MAX_BOOKMARKED_FILES ((buffer_size/(signed)sizeof(struct bookmarked_file_info))-1)
@@ -411,6 +411,7 @@ struct preferences old_prefs;
 
 static unsigned char *buffer;
 static long buffer_size;
+static long block_size = 0x1000;
 static unsigned char line_break[] = {0,0x20,9,0xB,0xC,'-'};
 static int display_columns; /* number of (pixel) columns on the display */
 static int display_lines; /* number of lines on the display */
@@ -481,6 +482,8 @@ static unsigned char* crop_at_width(const unsigned char* p)
 
     while (LINE_IS_NOT_FULL) {
         oldp = p;
+        if (BUFFER_OOB(p))
+           break;
         p = get_ucs(p, &ch);
         ADVANCE_COUNTERS(ch);
     }
@@ -666,7 +669,11 @@ static unsigned char* find_next_line(const unsigned char* cur_line, bool *is_sho
             next_line++;
 
     if (BUFFER_OOB(next_line))
+    {
+        if (BUFFER_EOF() && next_line != cur_line)
+            return (unsigned char*) next_line;
         return NULL;
+    }
 
     if (is_short)
         *is_short = false;
@@ -1517,6 +1524,13 @@ enum plugin_status plugin_start(const void* file)
 
     /* get the plugin buffer */
     buffer = rb->plugin_get_buffer((size_t *)&buffer_size);
+    if (buffer_size == 0)
+    {
+        rb->splash(HZ, "buffer does not allocate !!");
+        return PLUGIN_ERROR;
+    }
+    block_size = buffer_size / 3;
+    buffer_size = 3 * block_size;
 
     if (!file)
         return PLUGIN_ERROR;