diff --git a/Tools/AP_Bootloader/bl_protocol.cpp b/Tools/AP_Bootloader/bl_protocol.cpp
index 0912652e65..cef0b5a2c8 100644
--- a/Tools/AP_Bootloader/bl_protocol.cpp
+++ b/Tools/AP_Bootloader/bl_protocol.cpp
@@ -212,6 +212,8 @@ jump_to_app()
         return;
     }
 
+    flash_set_keep_unlocked(false);
+    
     led_set(LED_OFF);
 
     /* kill the systick timer */
@@ -296,28 +298,6 @@ cout_word(uint32_t val)
     cout((uint8_t *)&val, 4);
 }
 
-static int
-cin_word(uint32_t *wp, unsigned timeout)
-{
-    union {
-        uint32_t w;
-        uint8_t b[4];
-    } u;
-
-    for (unsigned i = 0; i < 4; i++) {
-        int c = cin(timeout);
-
-        if (c < 0) {
-            return c;
-        }
-
-        u.b[i] = c & 0xff;
-    }
-
-    *wp = u.w;
-    return 0;
-}
-
 static uint32_t
 crc32(const uint8_t *src, unsigned len, unsigned state)
 {
@@ -476,6 +456,8 @@ bootloader(unsigned timeout)
                 goto cmd_bad;
             }
 
+            flash_set_keep_unlocked(true);
+
             // clear the bootloader LED while erasing - it stops blinking at random
             // and that's confusing
             led_set(LED_OFF);
@@ -553,7 +535,6 @@ bootloader(unsigned timeout)
             }
 
             arg /= 4;
-
             for (int i = 0; i < arg; i++) {
                 // program the word
                 flash_func_write_word(address, flash_buffer.w[i]);
diff --git a/Tools/AP_Bootloader/support.cpp b/Tools/AP_Bootloader/support.cpp
index a9556055bd..86772257df 100644
--- a/Tools/AP_Bootloader/support.cpp
+++ b/Tools/AP_Bootloader/support.cpp
@@ -17,12 +17,22 @@ int16_t cin(unsigned timeout_ms)
 {
     uint8_t b = 0;
     if (chnReadTimeout(&SDU1, &b, 1, MS2ST(timeout_ms)) != 1) {
-        chThdSleepMilliseconds(1);
+        chThdSleepMicroseconds(100);
         return -1;
     }
     return b;
 }
 
+int cin_word(uint32_t *wp, unsigned timeout_ms)
+{
+    if (chnReadTimeout(&SDU1, (uint8_t *)wp, 4, MS2ST(timeout_ms)) != 4) {
+        chThdSleepMicroseconds(100);
+        return -1;
+    }
+    return 0;
+}
+
+
 void cout(uint8_t *data, uint32_t len)
 {
     chnWriteTimeout(&SDU1, data, len, MS2ST(100));
@@ -51,6 +61,10 @@ void flash_init(void)
     }
 }
 
+void flash_set_keep_unlocked(bool set)
+{
+    stm32_flash_keep_unlocked(set);
+}
 
 /*
   read a word at offset relative to FLASH_BOOTLOADER_LOAD_KB
diff --git a/Tools/AP_Bootloader/support.h b/Tools/AP_Bootloader/support.h
index 744aab8b27..be153bde2e 100644
--- a/Tools/AP_Bootloader/support.h
+++ b/Tools/AP_Bootloader/support.h
@@ -13,6 +13,7 @@ struct boardinfo {
 extern struct boardinfo board_info;
 
 int16_t cin(unsigned timeout_ms);
+int cin_word(uint32_t *wp, unsigned timeout_ms);
 void cout(uint8_t *data, uint32_t len);
 void cfini(void);
 
@@ -24,6 +25,7 @@ uint32_t flash_func_sector_size(uint32_t sector);
 void flash_func_erase_sector(uint32_t sector);
 uint32_t flash_func_read_otp(uint32_t idx);
 uint32_t flash_func_read_sn(uint32_t idx);
+void flash_set_keep_unlocked(bool);
 
 uint32_t get_mcu_id(void);
 uint32_t get_mcu_desc(uint32_t len, uint8_t *buf);