diff --git a/firmware/Cargo.lock b/firmware/Cargo.lock
index b5090be..f3b076c 100644
--- a/firmware/Cargo.lock
+++ b/firmware/Cargo.lock
@@ -1,6 +1,6 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
-version = 3
+version = 4
 
 [[package]]
 name = "aead"
@@ -215,6 +215,16 @@ dependencies = [
  "inout",
 ]
 
+[[package]]
+name = "const-hex"
+version = "1.14.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4b0485bab839b018a8f1723fc5391819fea5f8f0f32288ef8a735fd096b6160c"
+dependencies = [
+ "cfg-if",
+ "cpufeatures",
+]
+
 [[package]]
 name = "const-oid"
 version = "0.9.6"
@@ -2073,6 +2083,7 @@ name = "touch-n-drink"
 version = "0.2.0"
 dependencies = [
  "chrono",
+ "const-hex",
  "display-interface",
  "embassy-embedded-hal",
  "embassy-executor",
@@ -2093,7 +2104,6 @@ dependencies = [
  "esp-storage",
  "esp-wifi",
  "git2",
- "hex",
  "log",
  "maybe-async-cfg",
  "pn532",
diff --git a/firmware/Cargo.toml b/firmware/Cargo.toml
index 440ec2c..1efcc60 100644
--- a/firmware/Cargo.toml
+++ b/firmware/Cargo.toml
@@ -64,7 +64,7 @@ esp-partition-table = "0.1"
 esp-println = { version = "0.12", features = ["esp32c3", "log"] }
 esp-storage = { version = "0.4", features = ["esp32c3"] }
 esp-wifi = { version = "0.11", default-features = false, features = ["esp32c3", "esp-alloc", "log", "wifi"] }
-hex = { version = "0.4", default-features = false, features = ["alloc"] }
+const-hex = { version = "1.14", default-features = false }
 log = { version = "0.4", features = ["release_max_level_info"] }
 pn532 = "0.4"
 rand_core = "0.6"
diff --git a/firmware/src/nfc.rs b/firmware/src/nfc.rs
index 2b105ce..c37ed52 100644
--- a/firmware/src/nfc.rs
+++ b/firmware/src/nfc.rs
@@ -1,13 +1,13 @@
 // Use custom pn532 driver instead of pn532 crate
 use crate::pn532;
 
+use const_hex::FromHex;
 use core::convert::Infallible;
 use core::fmt::{self, Debug};
 use core::str::FromStr;
 use embassy_time::{Duration, Timer};
 use embedded_hal_async::digital::Wait;
 use embedded_hal_async::i2c::I2c;
-use hex::FromHex;
 use log::{debug, info, warn};
 use pn532::{Error as Pn532Error, I2CInterfaceWithIrq, Pn532, Request, SAMMode};