diff --git a/frontends/moa-minifb/Cargo.toml b/frontends/moa-minifb/Cargo.toml
index 59c3cde..92bb5f3 100644
--- a/frontends/moa-minifb/Cargo.toml
+++ b/frontends/moa-minifb/Cargo.toml
@@ -10,5 +10,5 @@ default-run = "moa-genesis"
 moa = { path = "../../" }
 moa-common = { path = "../moa-common/", features = ["audio"] }
 minifb = "0.19"
-clap = "3.0.0-beta.5"
+clap = "3.2.20"
 
diff --git a/frontends/moa-minifb/src/bin/moa-genesis.rs b/frontends/moa-minifb/src/bin/moa-genesis.rs
index e240168..b5b2e94 100644
--- a/frontends/moa-minifb/src/bin/moa-genesis.rs
+++ b/frontends/moa-minifb/src/bin/moa-genesis.rs
@@ -1,10 +1,13 @@
 
+use clap::Arg;
+
 use moa_minifb;
 use moa::machines::genesis::{build_genesis, SegaGenesisOptions};
 
 fn main() {
     let matches = moa_minifb::new("Sega Genesis/Mega Drive Emulator")
-        .arg("<ROM>        'ROM file to load (must be flat binary)'")
+        .arg(Arg::new("ROM")
+            .help("ROM file to load (must be flat binary)"))
         .get_matches();
 
     let mut options = SegaGenesisOptions::new();
diff --git a/frontends/moa-minifb/src/bin/moa-trs80.rs b/frontends/moa-minifb/src/bin/moa-trs80.rs
index aebb99a..40e4539 100644
--- a/frontends/moa-minifb/src/bin/moa-trs80.rs
+++ b/frontends/moa-minifb/src/bin/moa-trs80.rs
@@ -1,10 +1,17 @@
 
+use clap::Arg;
+
 use moa_minifb;
 use moa::machines::trs80::{build_trs80, Trs80Options};
 
 fn main() {
     let matches = moa_minifb::new("TRS-80 Emulator")
-        .arg("-r, --rom=[FILE]        'ROM file to load at the start of memory'")
+        .arg(Arg::new("ROM")
+            .short('r')
+            .long("rom")
+            .takes_value(true)
+            .value_name("FILE")
+            .help("ROM file to load at the start of memory"))
         .get_matches();
 
     let mut options = Trs80Options::new();
diff --git a/frontends/moa-minifb/src/lib.rs b/frontends/moa-minifb/src/lib.rs
index 514b5d3..680317d 100644
--- a/frontends/moa-minifb/src/lib.rs
+++ b/frontends/moa-minifb/src/lib.rs
@@ -5,7 +5,7 @@ use std::time::Duration;
 use std::sync::{Arc, Mutex};
 
 use minifb::{self, Key};
-use clap::{App, ArgMatches};
+use clap::{App, Arg, ArgMatches};
 
 use moa::error::Error;
 use moa::system::System;
@@ -28,11 +28,28 @@ const HEIGHT: u32 = 224;
 
 pub fn new(name: &str) -> App {
     App::new(name)
-        .arg("-s, --scale=[1,2,4]    'Scale the screen'")
-        .arg("-t, --threaded         'Run the simulation in a separate thread'")
-        .arg("-x, --speed=[]         'Adjust the speed of the simulation'")
-        .arg("-d, --debugger         'Start the debugger before running machine'")
-        .arg("-a, --disable-audio    'Disable audio output'")
+        .arg(Arg::new("scale")
+            .short('s')
+            .long("scale")
+            .takes_value(true)
+            .help("Scale the screen"))
+        .arg(Arg::new("threaded")
+            .short('t')
+            .long("threaded")
+            .help("Run the simulation in a separate thread"))
+        .arg(Arg::new("speed")
+            .short('x')
+            .long("speed")
+            .takes_value(true)
+            .help("Adjust the speed of the simulation"))
+        .arg(Arg::new("debugger")
+            .short('d')
+            .long("debugger")
+            .help("Start the debugger before running machine"))
+        .arg(Arg::new("disable-audio")
+            .short('a')
+            .long("disable-audio")
+            .help("Disable audio output"))
 }
 
 pub fn run<I>(matches: ArgMatches, init: I) where I: FnOnce(&mut MiniFrontendBuilder) -> Result<System, Error> + Send + 'static {
@@ -184,6 +201,7 @@ impl MiniFrontend {
             Some(1) => minifb::Scale::X1,
             Some(2) => minifb::Scale::X2,
             Some(4) => minifb::Scale::X4,
+            Some(8) => minifb::Scale::X8,
             _ => minifb::Scale::X2,
         };
 
diff --git a/todo.txt b/todo.txt
index 7e030f5..a2e4d14 100644
--- a/todo.txt
+++ b/todo.txt
@@ -83,7 +83,7 @@ Macintosh:
 
     * check all instructions in the docs
 
-    * unimplemented:  BFFFO, BFINS, CHK, ILLEGAL, NBCD, NEGX, RTR, RTD
+    * unimplemented:  BFFFO, BFINS, NBCD, RTD
     * >=MC68020 undecoded & unimplemented: BKPT, CALLM, CAS, CAS2, CHK2, CMP2, RTM, PACK, TRAPcc, UNPK
 
     * add support for MMU