diff --git a/Cargo.toml b/Cargo.toml
index 4db5d2b..9471960 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -10,7 +10,7 @@ license = "Apache-2.0"
 [dependencies]
 cortex-m = { version = "0.7" }
 cfg-if = "1"
-derive-mmio = { git = "https://github.com/knurling-rs/derive-mmio.git" }
+derive-mmio = { git = "https://github.com/knurling-rs/derive-mmio.git",  version = "0.6" }
 bitbybit = "1.3"
 arbitrary-int = "1.3"
 static_assertions = "1.1"
diff --git a/src/i2c/regs.rs b/src/i2c/regs.rs
index 7c56e5c..f824481 100644
--- a/src/i2c/regs.rs
+++ b/src/i2c/regs.rs
@@ -631,7 +631,7 @@ pub struct I2c {
 
     _reserved_0: [u32; 0x2D],
 
-    #[mmio(inner)]
+    #[mmio(Inner)]
     slave: slave::I2cSlave,
 
     #[cfg(feature = "vor1x")]