diff --git a/espflash/src/cli/mod.rs b/espflash/src/cli/mod.rs
index 9a7923da..0e5956a5 100644
--- a/espflash/src/cli/mod.rs
+++ b/espflash/src/cli/mod.rs
@@ -37,14 +37,8 @@ use crate::{
     elf::ElfFirmwareImage,
     error::{Error, MissingPartition, MissingPartitionTable},
     flasher::{
-        parse_partition_table,
-        FlashData,
-        FlashFrequency,
-        FlashMode,
-        FlashSettings,
-        FlashSize,
-        Flasher,
-        ProgressCallbacks,
+        parse_partition_table, FlashData, FlashFrequency, FlashMode, FlashSettings, FlashSize,
+        Flasher, ProgressCallbacks,
     },
     targets::{Chip, XtalFrequency},
 };
@@ -300,6 +294,7 @@ pub struct ChecksumMd5Args {
 
 /// Parses an integer, in base-10 or hexadecimal format, into a [u32]
 pub fn parse_u32(input: &str) -> Result<u32, ParseIntError> {
+    let input: &str = &input.replace('_', "");
     let (s, radix) = if input.len() > 2 && matches!(&input[0..2], "0x" | "0X") {
         (&input[2..], 16)
     } else {
@@ -892,6 +887,9 @@ mod test {
         // Decimal
         assert_eq!(parse_u32("1234"), Ok(1234));
         assert_eq!(parse_u32("0"), Ok(0));
+        // Underscores
+        assert_eq!(parse_u32("12_34"), Ok(1234));
+        assert_eq!(parse_u32("0X12_34"), Ok(0x1234));
         // Errors
         assert!(parse_u32("").is_err());
         assert!(parse_u32("0x").is_err());