diff --git a/sim/src/c.rs b/sim/src/c.rs
new file mode 100644
index 0000000..7ddb21b
--- /dev/null
+++ b/sim/src/c.rs
@@ -0,0 +1,50 @@
+/// Interface wrappers to C API entering to the bootloader
+
+use area::AreaDesc;
+use flash::Flash;
+use libc;
+
+/// Invoke the bootloader on this flash device.
+pub fn boot_go(flash: &mut Flash, areadesc: &AreaDesc) -> i32 {
+    unsafe { raw::invoke_boot_go(flash as *mut _ as *mut libc::c_void,
+                                 &areadesc.get_c() as *const _) as i32 }
+}
+
+/// Setter/getter for the flash counter.  This isn't thread safe.
+pub fn get_flash_counter() -> i32 {
+    unsafe { raw::flash_counter as i32 }
+}
+
+/// Set the flash counter.  Zero indicates the flash should not be interrupted.  The counter will
+/// then go negative for each flash operation.
+pub fn set_flash_counter(counter: i32) {
+    unsafe { raw::flash_counter = counter as libc::c_int };
+}
+
+pub fn boot_trailer_sz() -> u32 {
+    unsafe { raw::boot_trailer_sz(raw::sim_flash_align) }
+}
+
+pub fn get_sim_flash_align() -> u8 {
+    unsafe { raw::sim_flash_align }
+}
+
+pub fn set_sim_flash_align(align: u8) {
+    unsafe { raw::sim_flash_align = align };
+}
+
+mod raw {
+    use area::CAreaDesc;
+    use libc;
+
+    extern "C" {
+        // This generates a warning about `CAreaDesc` not being foreign safe.  There doesn't appear to
+        // be any way to get rid of this warning.  See https://github.com/rust-lang/rust/issues/34798
+        // for information and tracking.
+        pub fn invoke_boot_go(flash: *mut libc::c_void, areadesc: *const CAreaDesc) -> libc::c_int;
+        pub static mut flash_counter: libc::c_int;
+
+        pub static mut sim_flash_align: u8;
+        pub fn boot_trailer_sz(min_write_sz: u8) -> u32;
+    }
+}