flash: fix the flash sector size for SPEC

include/flash.h

@@ -11,7 +11,7 @@
 
 #include "types.h"
 
-#define FLASH_BLOCKSIZE 512
+#define FLASH_BLOCKSIZE 65536
 
 /* Flash interface functions */
 void	flash_init(void);

tools/sdbfs.README

@@ -30,6 +30,10 @@ To create the filesystem image: "gensdbfs tools/sdbfs /tmp/sdb-wrpc.bin"
 (please note that empty files have no data to be stored, so no space is
 wasted on disk for them and the output file is short).
 
+To create the flash filesystem image, don't forget about setting the sector
+size. For flash chip on SPEC card, it is 64k:
+gensdbfs -b 65536 tools/sdbfs /tmp/sdb-wrpc.bin
+
 To check: "sdb-read -l /tmp/sdb-wrpc.bin":
 
    46696c6544617461:2e202020 @ 00000000-0000037f .
@@ -56,4 +60,4 @@ The next boot of lm32 will show it found the files:
    file 0x63616c69 @  768, name calibration
 
 To read the flash: "tools/flash-read 0 320 > /tmp/flash.bin",
-and then check the flash image file: "sdb-read -l /tmp/flash.bin".
\ No newline at end of file
+and then check the flash image file: "sdb-read -l /tmp/flash.bin".