diff --git a/core/Cargo.toml b/core/Cargo.toml
index 414917a..bc4714a 100644
--- a/core/Cargo.toml
+++ b/core/Cargo.toml
@@ -15,7 +15,7 @@ categories = [
 license = "MIT OR Apache-2.0"
 
 [dependencies]
-cortex-m = { version = "0.6.0", optional = true }
+cortex-m = { version = "0.7.0", optional = true }
 
 [dependencies.defmt]
 version = "0.3.0"
diff --git a/core/src/lib.rs b/core/src/lib.rs
index 49ee1bd..e735e3c 100644
--- a/core/src/lib.rs
+++ b/core/src/lib.rs
@@ -95,7 +95,7 @@
 //! implemented by disabling interrupts. The critical sections are very short, a few instructions at
 //! most, so they should make no difference to most applications.
 
-#![cfg_attr(not(feature = "std"), no_std)]
+#![no_std]
 #![deny(missing_docs)]
 #![deny(warnings)]
 
diff --git a/core/src/vusize.rs b/core/src/vusize.rs
index f8fa73c..b86e0da 100644
--- a/core/src/vusize.rs
+++ b/core/src/vusize.rs
@@ -154,19 +154,6 @@ pub fn encoded_len(value: usize) -> usize {
     }
 }
 
-/// Get the length of an encoded `usize` for the given value in bytes.
-#[cfg(target_pointer_width = "8")]
-pub fn encoded_len(value: usize) -> usize {
-    // I don't think you can have targets with 8 bit pointers in rust,
-    // but just in case, 0..=127 would fit in one byte, and 128..=255
-    // would fit in two.
-    if (value & 0x80) == 0x80 {
-        2
-    } else {
-        1
-    }
-}
-
 /// Encode the given usize to the `slice`, using `length` bytes for encoding.
 ///
 /// ## Safety