diff --git a/Changes.md b/Changes.md
index 8659c20..226f85c 100644
--- a/Changes.md
+++ b/Changes.md
@@ -1,3 +1,8 @@
+## 0.0.13
+
+- It's now possible to set `cross-version` to a git ref like a commit hash or `HEAD`. This will
+  install `cross` from its git repo.
+
 ## 0.0.12 - 2024-02-25
 
 - Bumped the version of `actions/cache` used in this action to v4. The v3 version uses Node 16,
diff --git a/README.md b/README.md
index cb0f9e1..2bf3308 100644
--- a/README.md
+++ b/README.md
@@ -55,16 +55,16 @@ jobs:
 
 This action takes the following parameters:
 
-| Key                 | Type                                           | Required? | Description                                                                                                                                                                       |
-| ------------------- | ---------------------------------------------- | --------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| `command`           | string (one of `build`, `test`, or `both`)     | no        | The command(s) to run. The default is `build`. Running the `test` command will fail with \*BSD targets, non-x86 Windows, and macOS ARM.                                           |
-| `target`            | string                                         | yes       | The target triple to compile for. This should be one of the targets found by running `rustup target list`.                                                                        |
-| `working-directory` | string                                         | no        | The working directory in which to run the `cargo` or `cross` commands. Defaults to the current directory (`.`).                                                                   |
-| `toolchain`         | string (one of `stable`, `beta`, or `nightly`) | no        | The Rust toolchain version to install. The default is `stable`.                                                                                                                   |
-| `GITHUB_TOKEN`      | string                                         | no        | Defaults to the value of `${{ github.token }}`.                                                                                                                                   |
-| `args`              | string                                         | no        | A string-separated list of arguments to be passed to `cross build`, like `--release --locked`.                                                                                    |
-| `strip`             | boolean (`true` or `false`)                    | no        | If this is true, then the resulting binaries will be stripped if possible. This is only possible for binaries which weren't cross-compiled.                                       |
-| `cross-version`     | string                                         | no        | This can be used to set the version of `cross` to use. If specified, it should be a specific `cross` release tag. If this is not set then the latest version will always be used. |
+| Key                 | Type                                           | Required? | Description                                                                                                                                                                                                                                                                                                                                   |
+| ------------------- | ---------------------------------------------- | --------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
+| `command`           | string (one of `build`, `test`, or `both`)     | no        | The command(s) to run. The default is `build`. Running the `test` command will fail with \*BSD targets, non-x86 Windows, and macOS ARM.                                                                                                                                                                                                       |
+| `target`            | string                                         | yes       | The target triple to compile for. This should be one of the targets found by running `rustup target list`.                                                                                                                                                                                                                                    |
+| `working-directory` | string                                         | no        | The working directory in which to run the `cargo` or `cross` commands. Defaults to the current directory (`.`).                                                                                                                                                                                                                               |
+| `toolchain`         | string (one of `stable`, `beta`, or `nightly`) | no        | The Rust toolchain version to install. The default is `stable`.                                                                                                                                                                                                                                                                               |
+| `GITHUB_TOKEN`      | string                                         | no        | Defaults to the value of `${{ github.token }}`.                                                                                                                                                                                                                                                                                               |
+| `args`              | string                                         | no        | A string-separated list of arguments to be passed to `cross build`, like `--release --locked`.                                                                                                                                                                                                                                                |
+| `strip`             | boolean (`true` or `false`)                    | no        | If this is true, then the resulting binaries will be stripped if possible. This is only possible for binaries which weren't cross-compiled.                                                                                                                                                                                                   |
+| `cross-version`     | string                                         | no        | This can be used to set the version of `cross` to use. If specified, it should be a specific `cross` release tag (like `v0.2.3`) or a git ref (commit hash, `HEAD`, etc.). If this is not set then the latest released version will always be used. If this is set to a git ref then the version corresponding to that ref will be installed. |
 
 ## How it Works
 
diff --git a/install-cross-nix.sh b/install-cross-nix.sh
index cabd99c..2f73c01 100755
--- a/install-cross-nix.sh
+++ b/install-cross-nix.sh
@@ -1,3 +1,5 @@
+#!/bin/bash
+
 set -e
 set -x
 set -o pipefail
@@ -5,12 +7,19 @@ set -o pipefail
 CROSS_DIR="$1"
 VERSION="$2"
 
+cd "$CROSS_DIR"
+
+if [[ -n "$VERSION" ]] && ! [[ "$VERSION" =~ ^v ]]; then
+    cargo install cross --git https://github.com/cross-rs/cross --rev "$VERSION"
+    mv "$HOME/.cargo/bin/cross" .
+    exit 0
+fi
+
 VERSION_ARGS=""
 if [ -n "$VERSION" ]; then
     VERSION_ARGS="--tag $VERSION"
 fi
 
-cd "$CROSS_DIR"
 export TARGET=.
 curl --silent --location \
      https://raw.githubusercontent.com/houseabsolute/ubi/master/bootstrap/bootstrap-ubi.sh |