Add R on the main menu to boot Swiss and leave the test app

Getting back to Swiss previously meant power-cycling the console.  R boots
/boot.dol from the SD card directly.

It reuses netboot_boot_file(), so there is ONE DOL launcher and one set of
safety checks (MEM1 entry point, section overlap against the reserved staging
region, libfat unmounted before the jump) rather than a second copy to keep in
step.

Confirmed rather than one-touch, and main-menu only: R is an easy trigger to
catch by accident, test results are not saved anywhere, and losing a full run
to a stray press is worse than one extra button press.  Inside a suite R would
be easy to hit while navigating, so it is ignored there.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

gc_bba_test/README.md

@@ -73,6 +73,19 @@ Builds clean (no warnings) with devkitPPC 16.1.0 / GCC 16 in the devcontainer:
 
 `.gitignore` excludes the build products — run `make` to produce the `.dol`.
 
+## Boot Swiss (R button)
+
+**R** on the main menu boots `/boot.dol` from the SD card and leaves the test
+app, so you can get back to Swiss without power-cycling the console.
+
+It asks for confirmation (A to go, B to cancel). R is an easy trigger to catch
+by accident, test results are not saved anywhere, and losing a full run to a
+stray press is worse than one extra button. It is also main-menu only — inside
+a suite, R would be easy to hit while navigating.
+
+It uses the same `netboot_boot_file()` path as the post-update boot, so there
+is one DOL launcher and one set of safety checks rather than two.
+
 ## Self-update over the BBA (Z button)
 
 Press **Z**, then on the host:

gc_bba_test/source/main.c

@@ -9,6 +9,7 @@
  *   Y               clear all results
  *   B               back
  *   Z               self-update over the BBA, then relaunch (see netboot.c)
+ *   R               boot Swiss (/boot.dol) and leave the test app
  */
 #include <gccore.h>
 #include <stdio.h>
@@ -92,7 +93,8 @@ static void draw_main(int sel, const char *status)
 		}
 		printf("\n");
 	}
-	printf("\n" C_DIM "  A open   X run suite   START run all   Y clear   Z net-update\n" C_RESET);
+	printf("\n" C_DIM "  A open  X run suite  START all  Y clear  "
+	       "Z net-update  R Swiss\n" C_RESET);
 	if (status && *status) printf("\n  %s\n", status);
 }
 
@@ -198,6 +200,50 @@ static void do_netboot(char *status, size_t nstatus)
 	         "update saved, but /boot.dol would not boot (%d)", rc);
 }
 
+/* Boot Swiss from the SD card and leave the test app.
+ *
+ * Confirmed rather than one-touch: R is an easy trigger to catch by accident,
+ * test results are not saved anywhere, and losing a full run to a stray press
+ * is worse than one extra button. */
+static void do_boot_swiss(char *status, size_t nstatus)
+{
+	int rc;
+
+	printf("\n" C_HEAD "  Boot Swiss (/boot.dol)" C_RESET "\n\n");
+	printf("  A = confirm, B = cancel\n");
+	printf(C_DIM "  Test results are not saved and will be lost.\n" C_RESET);
+
+	for (;;) {
+		u16 d;
+		VIDEO_WaitVSync();
+		PAD_ScanPads();
+		d = PAD_ButtonsDown(0);
+		if (d & PAD_BUTTON_B) {
+			snprintf(status, nstatus, "boot cancelled");
+			return;
+		}
+		if (d & PAD_BUTTON_A)
+			break;
+	}
+
+	if (!s_stage) {
+		snprintf(status, nstatus, "staging region unavailable");
+		return;
+	}
+
+	printf("\n  booting /boot.dol ...\n");
+	VIDEO_WaitVSync();
+	VIDEO_WaitVSync();
+
+	/* Same path netboot uses after an update, so there is one DOL launcher
+	 * and one set of safety checks rather than two. */
+	rc = netboot_boot_file("/boot.dol", s_stage, s_stage_max, nb_status);
+
+	/* Only reached on refusal -- the launcher does not return on success. */
+	nb_pause("boot refused");
+	snprintf(status, nstatus, "/boot.dol would not boot (%d)", rc);
+}
+
 int main(void)
 {
 	int screen = 0;          /* 0 = main, 1 = suite detail */
@@ -233,6 +279,14 @@ int main(void)
 		down = PAD_ButtonsDown(0);
 		if (!down) continue;
 
+		if (!screen && (down & PAD_TRIGGER_R)) {
+			/* Main menu only: inside a suite R would be easy to hit
+			 * while navigating. */
+			do_boot_swiss(status, sizeof(status));
+			draw_main(sel, status);
+			continue;
+		}
+
 		if (down & PAD_TRIGGER_Z) {
 			/* Self-update: pull a new .dol over the BBA and launch it.
 			 * Staged in a malloc'd buffer rather than written in place --