diff --git a/pkgs/os-specific/linux/firmware/linux-firmware/source.nix b/pkgs/os-specific/linux/firmware/linux-firmware/source.nix
index 01ea40a5089a..4fcf64fae355 100644
--- a/pkgs/os-specific/linux/firmware/linux-firmware/source.nix
+++ b/pkgs/os-specific/linux/firmware/linux-firmware/source.nix
@@ -1,6 +1,6 @@
 # This file is autogenerated! Run ./update.sh to regenerate.
 {
-  version = "20230625";
-  sourceHash = "sha256-olRaUVnCri/sJU6ob+QgNxEZF8GzVxxEh8zdNJIZlYY=";
-  outputHash = "sha256-zSlMpAPbW7ewEBzDre47/7NJyy2pC0GSbkyOVVi+4gU=";
+  version = "unstable-2023-07-24";
+  sourceHash = "sha256-WyO/+fxQljfo6OXLC8/BomGmKtUQaJ1Lt9V5Fdv172g=";
+  outputHash = "sha256-wHWPSyqxP+MGmerbc2v/hclFFJ7qKCDsupK5GASjp8s=";
 }
diff --git a/pkgs/os-specific/linux/firmware/linux-firmware/update.sh b/pkgs/os-specific/linux/firmware/linux-firmware/update.sh
index 1fccc03e86be..0f11b7d069d1 100755
--- a/pkgs/os-specific/linux/firmware/linux-firmware/update.sh
+++ b/pkgs/os-specific/linux/firmware/linux-firmware/update.sh
@@ -5,7 +5,7 @@ cd "$(dirname "$(readlink -f "$0")")" || exit
 repo="https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git"
 
 # step 1: figure out the latest version from the tags
-if [ -z "$1" ]; then
+if [ -z "${1:-}" ]; then
   version="$(git ls-remote --refs --tags --sort refname "$repo" | tail -n1 | cut -f2 | cut -d '/' -f3)"
 else
   version=$1