diff --git a/tests/avr/Cargo.toml b/tests/avr/Cargo.toml
index ec1b0070..b057f58a 100644
--- a/tests/avr/Cargo.toml
+++ b/tests/avr/Cargo.toml
@@ -13,8 +13,6 @@ paste = "1"
 ufmt = "0.2"
 
 [target.avr-unknown-gnu-atmega2560.dependencies]
-# When updating the revision, the reminder to update rust-toolchain.toml to use
-# the same toolchain as https://github.com/Rahix/avr-hal/blob/HEAD/rust-toolchain.toml.
 arduino-hal = { git = "https://github.com/taiki-e/avr-hal.git", branch = "dev", features = ["arduino-mega2560"] }
 
 [workspace]
diff --git a/tests/avr/rust-toolchain.toml b/tests/avr/rust-toolchain.toml
index 50cd2f04..d5e80a6b 100644
--- a/tests/avr/rust-toolchain.toml
+++ b/tests/avr/rust-toolchain.toml
@@ -1,6 +1,6 @@
 [toolchain]
 # channel = "nightly-2022-07-10" # LLVM 14
 # channel = "nightly-2023-08-09" # LLVM 17
-channel = "nightly-2024-03-22" # LLVM 18
+channel = "nightly-2024-04-14" # LLVM 18
 components = ["rust-src"]
 profile = "minimal"