diff --git a/README.md b/README.md
index 776eebf..0fc99c9 100644
--- a/README.md
+++ b/README.md
@@ -47,12 +47,19 @@ The suite holds the two to being the same machine rather than taking it on trust
 the entire manifest through Voyager as well, with `--headless`, and requires it to satisfy
 every recorded result byte for byte.
 
-**Control, Alt and Delete is the reset button.** On real hardware it is not a key at all - a
-Voyager has a button on the case, and what a window has instead of a case is a gesture. Two
+**Control, Shift and R is the reset button.** On real hardware it is not a key at all - a
+Voyager has a button on the case, and what a window has instead of a case is a gesture. Three
 things follow from that. It must not be a key software might want, because a machine with a
-keyboard has function keys and something will eventually have a use for them. And it must not
-be reachable by accident, because restarting throws away everything in memory and a single
-key that does that sits one mistake away from losing work.
+keyboard has function keys and something will eventually have a use for them. It must not be
+reachable by accident, because restarting throws away everything in memory and a single key
+that does that sits one mistake away from losing work. And **it must be a gesture the host
+has no opinion about**.
+
+That last one rules out the obvious answer. Control, Alt and Delete has meant this since 1981
+and cannot be used: it is a secure attention key, reserved by every serious operating system
+so that it always reaches the system and never an application - precisely so a program cannot
+imitate a login screen. On Windows an application cannot see it without a kernel driver, and
+on Linux the desktop takes it. It is unavailable for the same reason it seemed right.
 
 It does exactly what writing to the machine port does: the machine starts the way it started,
 so the boot chain runs again and finds whatever the disk now says to run.
diff --git a/Source/Emulator/voyager.c b/Source/Emulator/voyager.c
index 5e7309a..6433123 100644
--- a/Source/Emulator/voyager.c
+++ b/Source/Emulator/voyager.c
@@ -140,8 +140,22 @@ static void drainKeyboard(void) {
 // memory, and a single key that does that sits one mistake away from losing work. Three keys
 // together are not pressed by mistake.
 //
-// Control, Alt and Delete, which has meant this since 1981 and is the one gesture nobody has
-// to be told the meaning of.
+// Control, Shift and R. It was Control, Alt and Delete, which has meant this since 1981 and
+// is the one gesture nobody has to be told the meaning of - AND WHICH CANNOT BE USED.
+//
+// It is a secure attention key. Every serious operating system reserves it so that it always
+// reaches the system and never an application, precisely so that a program cannot imitate a
+// login screen; on Windows an application cannot see it at all without a kernel driver, and
+// on Linux the desktop takes it. That is not an oversight to work around - it is the same
+// guarantee a reset button wants, being enforced one layer further down, and there is no
+// call this program can make that would win the argument.
+//
+// So the gesture has to be one the host has no opinion about. Control and Shift with a
+// letter is about as free as a combination gets: it is not window management, not a virtual
+// terminal switch, and not a shortcut any desktop claims by default.
+//
+// If a platform does send a character for it, nothing comes of that either - whatever
+// arrives is in memory that is about to be thrown away.
 //
 // What it does is what writing MACHINE_RESET does: the machine starts the way it started, so
 // the boot chain runs again and finds whatever the disk now says to run. Which is what makes
@@ -152,8 +166,8 @@ static int resetPending = 0;
 
 static void checkResetButton(void) {
     const int control = IsKeyDown(KEY_LEFT_CONTROL) || IsKeyDown(KEY_RIGHT_CONTROL);
-    const int alt = IsKeyDown(KEY_LEFT_ALT) || IsKeyDown(KEY_RIGHT_ALT);
-    if (control && alt && IsKeyPressed(KEY_DELETE)) {
+    const int shift = IsKeyDown(KEY_LEFT_SHIFT) || IsKeyDown(KEY_RIGHT_SHIFT);
+    if (control && shift && IsKeyPressed(KEY_R)) {
         requestReset();
         // Remembered as well as asked for, so that a machine waiting on a key can be woken
         // to go and notice it. See voyagerKey.