diff --git a/mik32_eeprom.py b/mik32_eeprom.py
index e8d1f7a..6b17780 100644
--- a/mik32_eeprom.py
+++ b/mik32_eeprom.py
@@ -203,6 +203,8 @@ def write_words(words: List[int], write_by_word = False, read_through_apb = Fals
 
     TODO: implement setting byte array offset, add error handling, 
     improve progress visualization, add option check page immidiately after writing
+
+    @return: return 0 if successful, 1 if failed
     """
     print(f"Write {len(words*4)} bytes")
     with OpenOcdTclRpc() as openocd:
diff --git a/mik32_spifi.py b/mik32_spifi.py
index f334894..214b675 100644
--- a/mik32_spifi.py
+++ b/mik32_spifi.py
@@ -334,7 +334,7 @@ def spifi_chip_erase(openocd: OpenOcdTclRpc):
     spifi_wait_intrq_timeout(openocd, "Timeout executing chip erase command")
 
 
-def spifi_read_data(openocd: OpenOcdTclRpc, address: int, byte_count: int, bin_data: List[int]):
+def spifi_read_data(openocd: OpenOcdTclRpc, address: int, byte_count: int, bin_data: List[int]) -> int:
     print("read data")
     read_data: List[int] = []
     openocd.write_word(SPIFI_CONFIG_ADDR, address)
@@ -374,6 +374,9 @@ def spifi_read_data(openocd: OpenOcdTclRpc, address: int, byte_count: int, bin_d
     for i in range(byte_count):
         if read_data[i] != bin_data[address + i]:
             print(f"DATA[{i+address}] = {read_data[i]:#0x} - ошибка")
+            return 1
+    
+    return 0
 
 
 def spifi_page_program(openocd: OpenOcdTclRpc, ByteAddress: int, data: List[int], byte_count: int):
@@ -444,13 +447,16 @@ def spifi_write_file(bytes: List[int], is_resume=True):
                 break
             print("address = ", address)
             spifi_write(openocd, address, bytes, 256)
-            spifi_read_data(openocd, address, 256, bytes)
+            if spifi_read_data(openocd, address, 256, bytes) == 1:
+                return 1
 
         if (len(bytes) % 256) != 0:
             print(
                 f"address = {address}, +{len(bytes) - address-1}[{address + len(bytes) - address-1}]")
             spifi_write(openocd, address, bytes, len(bytes) - address)
-            spifi_read_data(openocd, address, len(bytes) - address, bytes)
+            if spifi_read_data(openocd, address, len(bytes) - address, bytes) == 1:
+                return 1
         print("end")
         if is_resume:
             openocd.resume(0)
+    return 0
diff --git a/mik32_upload.py b/mik32_upload.py
index 74d36b0..0793458 100644
--- a/mik32_upload.py
+++ b/mik32_upload.py
@@ -39,6 +39,8 @@ def upload_file(filename: str, boot_source: str = "eeprom", is_resume=True) -> i
     @filename: full path to the file with hex or bin file format
     @boot_source: boot source, eeprom, ram or spifi, define memory block mapped to boot memory area (0x0 offset)
 
+    @return: return 0 if successful, 1 if failed
+
     TODO: Implement error handling
     """
 
@@ -71,8 +73,7 @@ def upload_file(filename: str, boot_source: str = "eeprom", is_resume=True) -> i
     if boot_source == "eeprom":
         result = write_words(bytes2words(get_content(filename)), is_resume)
     elif boot_source == "spifi":
-        spifi_write_file(get_content(filename), is_resume)
-        result = 0 # TODO
+        result = spifi_write_file(get_content(filename), is_resume)
     elif boot_source == "ram":
         write_file(filename, is_resume)
         result = 0 # TODO