From 1fa1b2076c27b86e1e0e058982af5e1d993569dc Mon Sep 17 00:00:00 2001
From: Ian Gulliver <github@flamingcow.io>
Date: Mon, 6 Apr 2026 09:19:26 +0900
Subject: [PATCH] Poll for BOOTSEL readiness instead of fixed sleep, load with
 -x

---
 cmd/load/main.go         | 29 +++++++++++++----------------
 lib/picotool/picotool.go | 15 ++++++++++++++-
 2 files changed, 27 insertions(+), 17 deletions(-)

diff --git a/cmd/load/main.go b/cmd/load/main.go
index 53ac69c..69a5865 100644
--- a/cmd/load/main.go
+++ b/cmd/load/main.go
@@ -116,7 +116,19 @@ func run(buildDir string) error {
 		}
 	}
 
-	time.Sleep(2 * time.Second)
+	for i := range 2 {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			errs[i] = picotool.WaitForBootsel(serials[i], 10*time.Second)
+		}()
+	}
+	wg.Wait()
+	for i, err := range errs {
+		if err != nil {
+			return fmt.Errorf("wait %s: %w", serials[i], err)
+		}
+	}
 
 	uf2s := []string{
 		filepath.Join(buildDir, "picomap.uf2"),
@@ -138,21 +150,6 @@ func run(buildDir string) error {
 		}
 	}
 
-	fmt.Println("Rebooting...")
-	for i := range 2 {
-		wg.Add(1)
-		go func() {
-			defer wg.Done()
-			errs[i] = picotool.Reboot(serials[i])
-		}()
-	}
-	wg.Wait()
-	for i, err := range errs {
-		if err != nil {
-			return fmt.Errorf("reboot %s: %w", serials[i], err)
-		}
-	}
-
 	fmt.Println("Done.")
 	return nil
 }
diff --git a/lib/picotool/picotool.go b/lib/picotool/picotool.go
index f9c38b4..92c98a5 100644
--- a/lib/picotool/picotool.go
+++ b/lib/picotool/picotool.go
@@ -3,10 +3,23 @@ package picotool
 import (
 	"fmt"
 	"os/exec"
+	"time"
 )
 
+func WaitForBootsel(serial string, timeout time.Duration) error {
+	deadline := time.Now().Add(timeout)
+	for time.Now().Before(deadline) {
+		cmd := exec.Command("picotool", "info", "--ser", serial)
+		if err := cmd.Run(); err == nil {
+			return nil
+		}
+		time.Sleep(100 * time.Millisecond)
+	}
+	return fmt.Errorf("device %s not found in BOOTSEL after %v", serial, timeout)
+}
+
 func Load(uf2Path string, serial string) error {
-	cmd := exec.Command("picotool", "load", uf2Path, "--ser", serial)
+	cmd := exec.Command("picotool", "load", uf2Path, "-x", "--ser", serial)
 	out, err := cmd.CombinedOutput()
 	if err != nil {
 		return fmt.Errorf("picotool load: %w\n%s", err, out)