Triggering the dfu bootloader works

memory.x

@@ -1,10 +1,23 @@
 MEMORY
 {
-  /* NOTE K = KiBi = 1024 bytes */
   FLASH : ORIGIN = 0x08000000, LENGTH = 256K 
-  RAM : ORIGIN = 0x20000000, LENGTH = 64K
+  UNINIT: ORIGIN = 0x20000000, LENGTH = 0x10
+  RAM : ORIGIN = 0x20000010, LENGTH = 64K - LENGTH(UNINIT)
 }
 
+SECTIONS {
+  .uninit_flags (NOLOAD) : ALIGN(4)
+  {
+    . = ALIGN(4);
+    __suninit_flags = .;
+    _dfu_magic = .; . += 4;
+    *(.uninit_flags .uninit_flags.*)
+    . = ALIGN(4);
+    __euninit_flags = .;
+  } > UNINIT
+}
+
+
 /* This is where the call stack will be allocated. */
 /* The stack is of the full descending type. */
 /* NOTE Do NOT modify `_stack_start` unless you know what you are doing */