diff --git a/cyw43/src/lib.rs b/cyw43/src/lib.rs
index 04847bfa..4a1d015a 100644
--- a/cyw43/src/lib.rs
+++ b/cyw43/src/lib.rs
@@ -1,6 +1,6 @@
 #![no_std]
 #![no_main]
-#![feature(async_fn_in_trait, type_alias_impl_trait, concat_bytes)]
+#![feature(async_fn_in_trait, type_alias_impl_trait)]
 #![allow(stable_features, unknown_lints, async_fn_in_trait)]
 #![deny(unused_must_use)]
 
diff --git a/cyw43/src/nvram.rs b/cyw43/src/nvram.rs
index 964a3128..3d1b5352 100644
--- a/cyw43/src/nvram.rs
+++ b/cyw43/src/nvram.rs
@@ -1,54 +1,48 @@
-macro_rules! nvram {
-    ($($s:literal,)*) => {
-        concat_bytes!($($s, b"\x00",)* b"\x00\x00")
-    };
-}
-
-pub static NVRAM: &'static [u8] = &*nvram!(
-    b"NVRAMRev=$Rev$",
-    b"manfid=0x2d0",
-    b"prodid=0x0727",
-    b"vendid=0x14e4",
-    b"devid=0x43e2",
-    b"boardtype=0x0887",
-    b"boardrev=0x1100",
-    b"boardnum=22",
-    b"macaddr=00:A0:50:b5:59:5e",
-    b"sromrev=11",
-    b"boardflags=0x00404001",
-    b"boardflags3=0x04000000",
-    b"xtalfreq=37400",
-    b"nocrc=1",
-    b"ag0=255",
-    b"aa2g=1",
-    b"ccode=ALL",
-    b"pa0itssit=0x20",
-    b"extpagain2g=0",
-    b"pa2ga0=-168,6649,-778",
-    b"AvVmid_c0=0x0,0xc8",
-    b"cckpwroffset0=5",
-    b"maxp2ga0=84",
-    b"txpwrbckof=6",
-    b"cckbw202gpo=0",
-    b"legofdmbw202gpo=0x66111111",
-    b"mcsbw202gpo=0x77711111",
-    b"propbw202gpo=0xdd",
-    b"ofdmdigfilttype=18",
-    b"ofdmdigfilttypebe=18",
-    b"papdmode=1",
-    b"papdvalidtest=1",
-    b"pacalidx2g=45",
-    b"papdepsoffset=-30",
-    b"papdendidx=58",
-    b"ltecxmux=0",
-    b"ltecxpadnum=0x0102",
-    b"ltecxfnsel=0x44",
-    b"ltecxgcigpio=0x01",
-    b"il0macaddr=00:90:4c:c5:12:38",
-    b"wl0id=0x431b",
-    b"deadman_to=0xffffffff",
-    b"muxenab=0x100",
-    b"spurconfig=0x3",
-    b"glitch_based_crsmin=1",
-    b"btc_mode=1",
-);
+pub static NVRAM: &'static [u8] = b"
+    NVRAMRev=$Rev$\x00\
+    manfid=0x2d0\x00\
+    prodid=0x0727\x00\
+    vendid=0x14e4\x00\
+    devid=0x43e2\x00\
+    boardtype=0x0887\x00\
+    boardrev=0x1100\x00\
+    boardnum=22\x00\
+    macaddr=00:A0:50:b5:59:5e\x00\
+    sromrev=11\x00\
+    boardflags=0x00404001\x00\
+    boardflags3=0x04000000\x00\
+    xtalfreq=37400\x00\
+    nocrc=1\x00\
+    ag0=255\x00\
+    aa2g=1\x00\
+    ccode=ALL\x00\
+    pa0itssit=0x20\x00\
+    extpagain2g=0\x00\
+    pa2ga0=-168,6649,-778\x00\
+    AvVmid_c0=0x0,0xc8\x00\
+    cckpwroffset0=5\x00\
+    maxp2ga0=84\x00\
+    txpwrbckof=6\x00\
+    cckbw202gpo=0\x00\
+    legofdmbw202gpo=0x66111111\x00\
+    mcsbw202gpo=0x77711111\x00\
+    propbw202gpo=0xdd\x00\
+    ofdmdigfilttype=18\x00\
+    ofdmdigfilttypebe=18\x00\
+    papdmode=1\x00\
+    papdvalidtest=1\x00\
+    pacalidx2g=45\x00\
+    papdepsoffset=-30\x00\
+    papdendidx=58\x00\
+    ltecxmux=0\x00\
+    ltecxpadnum=0x0102\x00\
+    ltecxfnsel=0x44\x00\
+    ltecxgcigpio=0x01\x00\
+    il0macaddr=00:90:4c:c5:12:38\x00\
+    wl0id=0x431b\x00\
+    deadman_to=0xffffffff\x00\
+    muxenab=0x100\x00\
+    spurconfig=0x3\x00\
+    glitch_based_crsmin=1\x00\
+    btc_mode=1\x00\
+    \x00";
diff --git a/embassy-stm32-wpan/src/lib.rs b/embassy-stm32-wpan/src/lib.rs
index 69a3d082..84cf0a02 100644
--- a/embassy-stm32-wpan/src/lib.rs
+++ b/embassy-stm32-wpan/src/lib.rs
@@ -4,7 +4,6 @@
     any(feature = "ble", feature = "mac"),
     allow(stable_features, unknown_lints, async_fn_in_trait)
 )]
-#![cfg_attr(feature = "mac", feature(type_alias_impl_trait, concat_bytes))]
 
 // This must go FIRST so that all the other modules see its macros.
 mod fmt;