diff --git a/build.sh b/build.sh
index 067a28a..1fada7e 100755
--- a/build.sh
+++ b/build.sh
@@ -71,6 +71,9 @@ build_update () {
     build_fpga
 
     pushd sw/update > /dev/null
+    if [ "$FORCE_CLEAN" = true ]; then
+        rm -f ./sc64.upd
+    fi
     INFO=""
     if [ ! -z "${GIT_BRANCH+x}" ]; then INFO+=" $GIT_BRANCH"; fi
     if [ ! -z "${GIT_TAG+x}" ]; then INFO+=" $GIT_TAG"; fi
diff --git a/sw/bootloader/src/startup.S b/sw/bootloader/src/startup.S
index 73f1e78..04f640b 100644
--- a/sw/bootloader/src/startup.S
+++ b/sw/bootloader/src/startup.S
@@ -19,7 +19,7 @@ header_crc:
 
     .org 0x20, 0x00
 header_text_info:
-    .ascii "n64boot SummerCart64"
+    .ascii "SC64 bootloader"
     .org 0x40, 0x00
 
 
diff --git a/sw/controller/build.sh b/sw/controller/build.sh
index b2345b3..18a31a8 100755
--- a/sw/controller/build.sh
+++ b/sw/controller/build.sh
@@ -1,6 +1,8 @@
 #!/bin/bash
 
 
+set -e
+
 case "$1" in
     all)
         make all -j -f loader.mk USER_FLAGS="$USER_FLAGS"
diff --git a/sw/controller/src/cfg.c b/sw/controller/src/cfg.c
index de94aa5..193025b 100644
--- a/sw/controller/src/cfg.c
+++ b/sw/controller/src/cfg.c
@@ -194,7 +194,7 @@ bool cfg_query (uint32_t *args) {
             args[1] = p.tv_type;
             break;
         case CFG_ID_FLASH_ERASE_BLOCK:
-            args[1] = 0xFFFFFFFF;
+            args[1] = FLASH_ERASE_BLOCK_SIZE;
             break;
         case CFG_ID_DD_DRIVE_TYPE:
             args[1] = dd_get_drive_type();
diff --git a/sw/controller/src/update.c b/sw/controller/src/update.c
index f36d160..52ab791 100644
--- a/sw/controller/src/update.c
+++ b/sw/controller/src/update.c
@@ -44,7 +44,7 @@ static uint32_t update_align (uint32_t value) {
 }
 
 static uint32_t update_checksum (uint32_t address, uint32_t length) {
-    uint8_t buffer[32];
+    uint8_t buffer[128];
     uint32_t block_size;
     uint32_t checksum = 0;
     hw_crc32_reset();
@@ -145,6 +145,40 @@ static void update_status_notify (update_status_t status) {
     }
 }
 
+static bool mcu_update (uint32_t address, uint32_t length) {
+    hw_flash_t buffer;
+    hw_flash_erase();
+    for (uint32_t offset = 0; offset < length; offset += sizeof(hw_flash_t)) {
+        fpga_mem_read(address + offset, sizeof(hw_flash_t), (uint8_t *) (&buffer));
+        hw_flash_program(offset, buffer);
+        if (hw_flash_read(offset) != buffer) {
+            return true;
+        }
+    }
+    return false;
+}
+
+static bool bootloader_update (uint32_t address, uint32_t length) {
+    uint8_t update_buffer[FPGA_MAX_MEM_TRANSFER];
+    uint8_t verify_buffer[FPGA_MAX_MEM_TRANSFER];
+    for (uint32_t offset = 0; offset < BOOTLOADER_LENGTH; offset += FLASH_ERASE_BLOCK_SIZE) {
+        flash_erase_block(BOOTLOADER_ADDRESS + offset);
+    }
+    for (uint32_t offset = 0; offset < length; offset += FPGA_MAX_MEM_TRANSFER) {
+        fpga_mem_copy(address + offset, BOOTLOADER_ADDRESS + offset, FPGA_MAX_MEM_TRANSFER);
+    }
+    for (uint32_t offset = 0; offset < length; offset += sizeof(verify_buffer)) {
+        fpga_mem_read(address + offset, sizeof(update_buffer), update_buffer);
+        fpga_mem_read(BOOTLOADER_ADDRESS + offset, sizeof(verify_buffer), verify_buffer);
+        for (int i = 0; i < sizeof(verify_buffer); i++) {
+            if (update_buffer[i] != verify_buffer[i]) {
+                return true;
+            }
+        }
+    }
+    return false;
+}
+
 
 update_error_t update_backup (uint32_t address, uint32_t *length) {
     uint32_t mcu_length;
@@ -247,17 +281,11 @@ void update_perform (void) {
     uint32_t length;
 
     if (parameters.flags & LOADER_FLAGS_UPDATE_MCU) {
-        hw_flash_t buffer;
         update_status_notify(UPDATE_STATUS_MCU);
         fpga_mem_read(parameters.mcu_address - 4, sizeof(length), (uint8_t *) (&length));
-        hw_flash_erase();
-        for (uint32_t offset = 0; offset < length; offset += sizeof(hw_flash_t)) {
-            fpga_mem_read(parameters.mcu_address + offset, sizeof(hw_flash_t), (uint8_t *) (&buffer));
-            hw_flash_program(offset, buffer);
-            if (hw_flash_read(offset) != buffer) {
-                update_status_notify(UPDATE_STATUS_ERROR);
-                while (1);
-            }
+        if (mcu_update(parameters.mcu_address, length)) {
+            update_status_notify(UPDATE_STATUS_ERROR);
+            while (1);
         }
     }
 
@@ -273,11 +301,9 @@ void update_perform (void) {
     if (parameters.flags & LOADER_FLAGS_UPDATE_BOOTLOADER) {
         update_status_notify(UPDATE_STATUS_BOOTLOADER);
         fpga_mem_read(parameters.bootloader_address - 4, sizeof(length), (uint8_t *) (&length));
-        for (uint32_t offset = 0; offset < BOOTLOADER_LENGTH; offset += FLASH_ERASE_BLOCK_SIZE) {
-            flash_erase_block(BOOTLOADER_ADDRESS + offset);
-        }
-        for (uint32_t offset = 0; offset < length; offset += FPGA_MAX_MEM_TRANSFER) {
-            fpga_mem_copy(parameters.bootloader_address + offset, BOOTLOADER_ADDRESS + offset, FPGA_MAX_MEM_TRANSFER);
+        if (bootloader_update(parameters.bootloader_address, length)) {
+            update_status_notify(UPDATE_STATUS_ERROR);
+            while (1);
         }
     }
 
diff --git a/sw/update/update.py b/sw/update/update.py
index ecae801..e0a41c3 100644
--- a/sw/update/update.py
+++ b/sw/update/update.py
@@ -1,3 +1,5 @@
+#!/usr/bin/env python3
+
 import argparse
 import math
 import os
@@ -7,6 +9,7 @@ from datetime import datetime
 from io import BufferedRandom
 
 
+
 class JedecError(Exception):
     pass