flash info

[asdfg]

hi,
i have used the following code for read and write in flash but i am getting error like ets Jan 8 2013,rst cause:4, boot mode:(3,2)
.
.wdt reset
.load 0x4010f000, len 1384, room 16
.tail 8
.chksum 0x2d
.csum 0x2d
.v09f0c112
.~ld.
spi_flash_erase_sector(0x3D);
spi_flash_erase_sector(0x3C);
delay(200);
spi_flash_write(0x3D000,(uint32*)buf1,16);
delay(200);
Serial.print("12");
spi_flash_write(0x3D014,(uint32*)buf2,16);
delay(200);
Serial.print("123");
spi_flash_write(0x3D030,(uint32*)buf3,16);
delay(200);
Serial.print("1234");
spi_flash_write(0x3D044,(uint32*)buf4,5);
pls give suggestion on this. Is there any other way to read and write user data permanently in esp8266?

[ESP_Xutao]

Hi；
3D,this flash area can't erase 3D ,if you choose user bin,if your user1.bin is 320KB,you must user flash area after 0x510000,id you erase 3D,it's error.So you should choose a correct area to use.