diff --git a/sim/simflash/src/lib.rs b/sim/simflash/src/lib.rs
index 1e9876c..df1020e 100644
--- a/sim/simflash/src/lib.rs
+++ b/sim/simflash/src/lib.rs
@@ -14,6 +14,7 @@
 use std::iter::Enumerate;
 use std::path::Path;
 use std::slice;
+use std::collections::HashMap;
 use pdump::HexDump;
 
 error_chain! {
@@ -130,6 +131,8 @@
 
 }
 
+pub type SimFlashMap = HashMap<u8, SimFlash>;
+
 impl Flash for SimFlash {
     /// The flash drivers tend to erase beyond the bounds of the given range.  Instead, we'll be
     /// strict, and make sure that the passed arguments are exactly at a sector boundary, otherwise