diff --git a/esp-link/cgiwebserver.c b/esp-link/cgiwebserver.c
index 8dbe042..de4f3f5 100644
--- a/esp-link/cgiwebserver.c
+++ b/esp-link/cgiwebserver.c
@@ -6,8 +6,9 @@
 #include "cgioptiboot.h"
 #include "multipart.h"
 #include "espfsformat.h"
+#include "config.h"
 
-int webServerMultipartCallback(MultipartCmd cmd, char *data, int dataLen, int position)
+int ICACHE_FLASH_ATTR webServerMultipartCallback(MultipartCmd cmd, char *data, int dataLen, int position)
 {
   switch(cmd)
   {
@@ -27,10 +28,38 @@ int webServerMultipartCallback(MultipartCmd cmd, char *data, int dataLen, int po
           data[p - position] = 0xFF; // clean espfs magic to mark as invalid
         }
       }
-      // TODO: flash write
+      
+      int spi_flash_addr = getUserPageSectionStart() + position;
+      int spi_flash_end_addr = spi_flash_addr + dataLen;
+      if( spi_flash_end_addr + dataLen >= getUserPageSectionEnd() )
+      {
+        os_printf("No more space in the flash!\n");
+        return 1;
+      }
+      
+      int ptr = 0;
+      while( spi_flash_addr < spi_flash_end_addr )
+      {
+        if (spi_flash_addr % SPI_FLASH_SEC_SIZE == 0){
+          spi_flash_erase_sector(spi_flash_addr/SPI_FLASH_SEC_SIZE);
+        }
+        
+        int max = (spi_flash_addr | (SPI_FLASH_SEC_SIZE - 1)) + 1;
+        int len = spi_flash_end_addr - spi_flash_addr;
+        if( spi_flash_end_addr > max )
+          len = max - spi_flash_addr;
+
+        spi_flash_write( spi_flash_addr, (uint32_t *)(data + ptr), len );
+        ptr += len;
+        spi_flash_addr += len;
+      }
+      
       break;
     case FILE_DONE:
-      // TODO: finalize changes, set back espfs magic
+      {
+        uint32_t magic = ESPFS_MAGIC;
+        spi_flash_write( (int)getUserPageSectionStart(), (uint32_t *)&magic, sizeof(uint32_t) );
+      }
       break;
   }
   return 0;
diff --git a/httpd/multipart.c b/httpd/multipart.c
index 813ac82..1198579 100644
--- a/httpd/multipart.c
+++ b/httpd/multipart.c
@@ -6,14 +6,14 @@
 
 #define BOUNDARY_SIZE 100
 
-void multipartAllocBoundaryBuffer(MultipartCtx * context)
+void ICACHE_FLASH_ATTR multipartAllocBoundaryBuffer(MultipartCtx * context)
 {
   if( context->boundaryBuffer == NULL )
     context->boundaryBuffer = (char *)os_malloc(3*BOUNDARY_SIZE + 1);
   context->boundaryBufferPtr = 0;
 }
 
-void multipartFreeBoundaryBuffer(MultipartCtx * context)
+void ICACHE_FLASH_ATTR multipartFreeBoundaryBuffer(MultipartCtx * context)
 {
   if( context->boundaryBuffer != NULL )
   {
@@ -22,7 +22,7 @@ void multipartFreeBoundaryBuffer(MultipartCtx * context)
   }
 }
 
-int multipartProcessBoundaryBuffer(MultipartCtx * context, char * boundary, char * buff, int len, int last)
+int ICACHE_FLASH_ATTR multipartProcessBoundaryBuffer(MultipartCtx * context, char * boundary, char * buff, int len, int last)
 {
   if( len != 0 )
   {