diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9db4285..4dd2cd7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Regression in `flash` command
 
+### Changed
+
+- Allow underscore `_` in number literals in command line
+
 ## [0.0.5] - 2023-07-31
 
 ### Added
diff --git a/src/main.rs b/src/main.rs
index ba33e6f..723124f 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -245,10 +245,11 @@ fn main() -> Result<()> {
 }
 
 pub fn parse_number(s: &str) -> std::result::Result<u32, String> {
-    if s.starts_with("0x") || s.starts_with("0X") {
+    let s = s.replace("_", "").to_lowercase();
+    if s.starts_with("0x") {
         Ok(u32::from_str_radix(&s[2..], 16)
             .unwrap_or_else(|_| panic!("error while parsering {s:?}")))
-    } else if s.starts_with("0b") || s.starts_with("0B") {
+    } else if s.starts_with("0b") {
         Ok(u32::from_str_radix(&s[2..], 2)
             .unwrap_or_else(|_| panic!("error while parsering {s:?}")))
     } else {