diff --git a/docs/release-notes.d/ptest.md b/docs/release-notes.d/ptest.md
new file mode 100644
index 000000000..caca800ec
--- /dev/null
+++ b/docs/release-notes.d/ptest.md
@@ -0,0 +1,8 @@
+- Update ptest to support test selection. Ptest can now be invoked with `list`
+  to show the available tests and `run` to run them. The `-t` argument will
+  select specific tests to run.
+- Allow sim tests to skip slow tests.  By setting `MCUBOOT_SKIP_SLOW_TESTS` in
+  the environment, the sim will skip two tests that are very slow.  In one
+  instance this reduces the test time from 2 hours to about 5 minutes.  These
+  slow tests are useful, in that they test bad powerdown recovery, but are
+  inconvenient when testing other areas.
diff --git a/ptest/Cargo.lock b/ptest/Cargo.lock
index faca3590a..84f0e485c 100644
--- a/ptest/Cargo.lock
+++ b/ptest/Cargo.lock
@@ -32,7 +32,7 @@ version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "d9b39be18770d11421cdb1b9947a45dd3f37e93092cbf377614828a319d5fee8"
 dependencies = [
- "hermit-abi",
+ "hermit-abi 0.1.19",
  "libc",
  "winapi",
 ]
@@ -58,6 +58,12 @@ dependencies = [
  "rustc-demangle",
 ]
 
+[[package]]
+name = "bitflags"
+version = "2.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf4b9d6a944f767f8e5e0db018570623c85f3d925ac718db4e06d0187adb21c1"
+
 [[package]]
 name = "cc"
 version = "1.0.73"
@@ -83,6 +89,43 @@ dependencies = [
  "winapi",
 ]
 
+[[package]]
+name = "clap"
+version = "4.1.11"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "42dfd32784433290c51d92c438bb72ea5063797fc3cc9a21a8c4346bebbb2098"
+dependencies = [
+ "bitflags",
+ "clap_derive",
+ "clap_lex",
+ "is-terminal",
+ "once_cell",
+ "strsim",
+ "termcolor",
+]
+
+[[package]]
+name = "clap_derive"
+version = "4.1.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fddf67631444a3a3e3e5ac51c36a5e01335302de677bd78759eaa90ab1f46644"
+dependencies = [
+ "heck",
+ "proc-macro-error",
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "clap_lex"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "033f6b7a4acb1f358c742aaca805c939ee73b4c6209ae4318ec7aca81c42e646"
+dependencies = [
+ "os_str_bytes",
+]
+
 [[package]]
 name = "env_logger"
 version = "0.9.0"
@@ -124,6 +167,12 @@ version = "0.26.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "78cc372d058dcf6d5ecd98510e7fbc9e5aec4d21de70f65fea8fecebcd881bd4"
 
+[[package]]
+name = "heck"
+version = "0.4.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "95505c38b4572b2d910cecb0281560f54b440a19336cbbcb27bf6ce6adc6f5a8"
+
 [[package]]
 name = "hermit-abi"
 version = "0.1.19"
@@ -133,12 +182,29 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "hermit-abi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d231dfb89cfffdbc30e7fc41579ed6066ad03abda9e567ccafae602b97ec5024"
+
 [[package]]
 name = "humantime"
 version = "2.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "9a3a5bfb195931eeb336b2a7b4d761daec841b97f947d34394601737a7bba5e4"
 
+[[package]]
+name = "is-terminal"
+version = "0.4.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f23ff5ef2b80d608d61efee834934d862cd92461afc0560dedf493e4c033738b"
+dependencies = [
+ "hermit-abi 0.3.9",
+ "libc",
+ "windows-sys",
+]
+
 [[package]]
 name = "libc"
 version = "0.2.126"
@@ -200,7 +266,7 @@ version = "1.13.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "19e64526ebdee182341572e50e9ad03965aa510cd94427a4549448f285e957a1"
 dependencies = [
- "hermit-abi",
+ "hermit-abi 0.1.19",
  "libc",
 ]
 
@@ -213,11 +279,47 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "once_cell"
+version = "1.19.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3fdb12b2476b595f9358c5161aa467c2438859caa136dec86c26fdd2efe17b92"
+
+[[package]]
+name = "os_str_bytes"
+version = "6.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2355d85b9a3786f481747ced0e0ff2ba35213a1f9bd406ed906554d7af805a1"
+
+[[package]]
+name = "proc-macro-error"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "da25490ff9892aab3fcf7c36f08cfb902dd3e71ca0f9f9517bea02a73a5ce38c"
+dependencies = [
+ "proc-macro-error-attr",
+ "proc-macro2",
+ "quote",
+ "syn",
+ "version_check",
+]
+
+[[package]]
+name = "proc-macro-error-attr"
+version = "1.0.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a1be40180e52ecc98ad80b184934baf3d0d29f979574e439af5a55274b35f869"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "version_check",
+]
+
 [[package]]
 name = "proc-macro2"
-version = "1.0.40"
+version = "1.0.79"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "dd96a1e8ed2596c337f8eae5f24924ec83f5ad5ab21ea8e455d3566c69fbcaf7"
+checksum = "e835ff2298f5721608eb1a980ecaee1aef2c132bf95ecc026a11b7bf3c01c02e"
 dependencies = [
  "unicode-ident",
 ]
@@ -227,6 +329,7 @@ name = "ptest"
 version = "0.1.0"
 dependencies = [
  "chrono",
+ "clap",
  "env_logger",
  "failure",
  "log",
@@ -273,6 +376,12 @@ version = "0.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "33ae9eec00137a8eed469fb4148acd9fc6ac8c3f9b110f52cd34698c8b5bfa0e"
 
+[[package]]
+name = "strsim"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "73473c0e59e6d5812c5dfe2a064a6444949f089e20eec9a2e5506596494e4623"
+
 [[package]]
 name = "syn"
 version = "1.0.98"
@@ -328,6 +437,12 @@ version = "0.2.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "957e51f3646910546462e67d5f7599b9e4fb8acdd304b087a6494730f9eebf04"
 
+[[package]]
+name = "version_check"
+version = "0.9.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
+
 [[package]]
 name = "wasi"
 version = "0.10.0+wasi-snapshot-preview1"
@@ -365,6 +480,72 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 
+[[package]]
+name = "windows-sys"
+version = "0.52.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "282be5f36a8ce781fad8c8ae18fa3f9beff57ec1b52cb3de0789201425d9a33d"
+dependencies = [
+ "windows-targets",
+]
+
+[[package]]
+name = "windows-targets"
+version = "0.52.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7dd37b7e5ab9018759f893a1952c9420d060016fc19a472b4bb20d1bdd694d1b"
+dependencies = [
+ "windows_aarch64_gnullvm",
+ "windows_aarch64_msvc",
+ "windows_i686_gnu",
+ "windows_i686_msvc",
+ "windows_x86_64_gnu",
+ "windows_x86_64_gnullvm",
+ "windows_x86_64_msvc",
+]
+
+[[package]]
+name = "windows_aarch64_gnullvm"
+version = "0.52.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bcf46cf4c365c6f2d1cc93ce535f2c8b244591df96ceee75d8e83deb70a9cac9"
+
+[[package]]
+name = "windows_aarch64_msvc"
+version = "0.52.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "da9f259dd3bcf6990b55bffd094c4f7235817ba4ceebde8e6d11cd0c5633b675"
+
+[[package]]
+name = "windows_i686_gnu"
+version = "0.52.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "b474d8268f99e0995f25b9f095bc7434632601028cf86590aea5c8a5cb7801d3"
+
+[[package]]
+name = "windows_i686_msvc"
+version = "0.52.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1515e9a29e5bed743cb4415a9ecf5dfca648ce85ee42e15873c3cd8610ff8e02"
+
+[[package]]
+name = "windows_x86_64_gnu"
+version = "0.52.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5eee091590e89cc02ad514ffe3ead9eb6b660aedca2183455434b93546371a03"
+
+[[package]]
+name = "windows_x86_64_gnullvm"
+version = "0.52.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77ca79f2451b49fa9e2af39f0747fe999fcda4f5e241b2898624dca97a1f2177"
+
+[[package]]
+name = "windows_x86_64_msvc"
+version = "0.52.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "32b752e52a2da0ddfbdbcc6fceadfeede4c939ed16d13e648833a61dfb611ed8"
+
 [[package]]
 name = "yaml-rust"
 version = "0.4.5"
diff --git a/ptest/Cargo.toml b/ptest/Cargo.toml
index 4086bf121..bb38f9332 100644
--- a/ptest/Cargo.toml
+++ b/ptest/Cargo.toml
@@ -12,3 +12,7 @@ log = "0.4.17"
 num_cpus = "1.13.1"
 std-semaphore = "0.1"
 yaml-rust = "0.4"
+
+[dependencies.clap]
+version = "4.0"
+features = ["derive"]
diff --git a/ptest/src/main.rs b/ptest/src/main.rs
index 053448bf8..9a75ccb74 100644
--- a/ptest/src/main.rs
+++ b/ptest/src/main.rs
@@ -11,6 +11,7 @@
 //! jobs->environment->strategy->matric->features
 
 use chrono::Local;
+use clap::{Parser, Subcommand};
 use log::{debug, error, warn};
 use std::{
     collections::HashSet,
@@ -37,7 +38,9 @@ type Result<T> = result::Result<T, failure::Error>;
 fn main() -> Result<()> {
     env_logger::init();
 
-    let workflow_text = fs::read_to_string("../.github/workflows/sim.yaml")?;
+    let args = Cli::parse();
+
+    let workflow_text = fs::read_to_string(&args.workflow)?;
     let workflow = YamlLoader::load_from_str(&workflow_text)?;
 
     let ncpus = num_cpus::get();
@@ -45,6 +48,18 @@ fn main() -> Result<()> {
 
     let matrix = Matrix::from_yaml(&workflow);
 
+    let matrix = if args.test.len() == 0 { matrix } else {
+        matrix.only(&args.test)
+    };
+
+    match args.command {
+        Commands::List => {
+            matrix.show();
+            return Ok(());
+        }
+        Commands::Run => (),
+    }
+
     let mut children = vec![];
     let state = State::new(matrix.envs.len());
     let st2 = state.clone();
@@ -76,6 +91,31 @@ fn main() -> Result<()> {
     Ok(())
 }
 
+/// The main Cli.
+#[derive(Debug, Parser)]
+#[command(name = "ptest")]
+#[command(about = "Run MCUboot CI tests stand alone")]
+struct Cli {
+    /// The workflow file to use.
+    #[arg(short, long, default_value = "../.github/workflows/sim.yaml")]
+    workflow: String,
+
+    /// The tests to run (defaults to all)
+    #[arg(short, long)]
+    test: Vec<usize>,
+
+    #[command(subcommand)]
+    command: Commands,
+}
+
+#[derive(Debug, Subcommand)]
+enum Commands {
+    /// Runs the tests.
+    Run,
+    /// List available tests.
+    List,
+}
+
 /// State, for printing status.
 struct State {
     running: HashSet<String>,
@@ -220,6 +260,27 @@ impl Matrix {
             envs,
         }
     }
+
+    /// Print out all of the feature sets.
+    fn show(&self) {
+        for (i, feature) in self.envs.iter().enumerate() {
+            println!("{:3}. {}", i + 1, feature.simple_textual());
+        }
+    }
+
+    /// Replace this matrix with one that only has the chosen tests in it. Note
+    /// that the original order is preserved, not that given in `pick`.
+    fn only(self, pick: &[usize]) -> Self {
+        let pick: HashSet<usize> = pick.iter().cloned().collect();
+        let envs: Vec<_> = self
+            .envs
+            .into_iter()
+            .enumerate()
+            .filter(|(ind, _)| pick.contains(&(ind + 1)))
+            .map(|(_, item)| item)
+            .collect();
+        Matrix { envs }
+    }
 }
 
 impl FeatureSet {
@@ -278,6 +339,18 @@ impl FeatureSet {
 
         buf
     }
+
+    /// Generate a simpler textual representation, without showing the environment.
+    fn simple_textual(&self) -> String {
+        use std::fmt::Write;
+
+        let mut buf = String::new();
+        for v in &self.values {
+            write!(&mut buf, " {}", v).unwrap();
+        }
+
+        buf
+    }
 }
 
 fn lookup_matrix(y: &Yaml) -> Option<&Vec<Yaml>> {
diff --git a/sim/src/image.rs b/sim/src/image.rs
index 632dfa568..270ef248a 100644
--- a/sim/src/image.rs
+++ b/sim/src/image.rs
@@ -689,6 +689,10 @@ impl Images {
         let mut fails = 0;
         let total_flash_ops = self.total_count.unwrap();
 
+        if skip_slow_test() {
+            return false;
+        }
+
         // Let's try an image halfway through.
         for i in 1 .. total_flash_ops {
             info!("Try interruption at {}", i);
@@ -775,6 +779,10 @@ impl Images {
 
         let mut fails = 0;
 
+        if skip_slow_test() {
+            return false;
+        }
+
         if self.is_swap_upgrade() {
             for i in 1 .. self.total_count.unwrap() {
                 info!("Try interruption at {}", i);
@@ -2314,3 +2322,14 @@ fn test_alignments() -> &'static [usize] {
 fn test_alignments() -> &'static [usize] {
     &[32]
 }
+
+/// For testing, some of the tests are quite slow. This will query for an
+/// environment variable `MCUBOOT_SKIP_SLOW_TESTS`, which can be set to avoid
+/// running these tests.
+fn skip_slow_test() -> bool {
+    if let Ok(_) = std::env::var("MCUBOOT_SKIP_SLOW_TESTS") {
+        true
+    } else {
+        false
+    }
+}