fix: Improve fastboot userspace reboot & sparse limits

Switch SparseMaxDownloadSize to a long and default it to uint.MaxValue, and clamp computed download sizes against both the host-side limit and the protocol (uint32) max. Adjust CLI and tests to use the new type and to apply the correct min/max. Improve reboot-to-userspace behavior: shorten the reconnect pause, print a waiting message, use EnsureUserspace for fastboot-target reboots, and add clearer error messages plus a final IsUserspace check after reconnect. Also bump FirmwareKit.Sparse to 1.0.1 and remove an AVB package reference.

Author: 13584452567

FastbootCLI/Program.cs

@@ -104,7 +104,7 @@ static void Main(string[] args)
             }
 
             using FastbootDriver util = new FastbootDriver(target);
-            if (sparseLimit.HasValue) FastbootDriver.SparseMaxDownloadSize = (int)Math.Min(int.MaxValue, sparseLimit.Value);
+            if (sparseLimit.HasValue) FastbootDriver.SparseMaxDownloadSize = Math.Min((long)uint.MaxValue, sparseLimit.Value);
 
             util.ReceivedFromDevice += (s, e) =>
             {
@@ -217,15 +217,24 @@ string GetPartition(string baseName)
 
                 case "reboot":
                     string targetStr = args.Count > 0 ? args[0] : "";
-                    util.Reboot(targetStr).ThrowIfError();
+                    if (targetStr == "fastboot")
+                    {
+                        Console.Error.WriteLine("waiting for any device >");
+                        util.EnsureUserspace();
+                    }
+                    else
+                    {
+                        util.Reboot(targetStr).ThrowIfError();
+                    }
                     break;
 
                 case "reboot-bootloader":
                     util.Reboot("bootloader").ThrowIfError();
                     break;
 
                 case "reboot-fastboot":
-                    util.Reboot("fastboot").ThrowIfError();
+                    Console.Error.WriteLine("waiting for any device >");
+                    util.EnsureUserspace();
                     break;
 
                 case "reboot-recovery":

FirmwareKit.Comm.Fastboot.Tests/FastbootInfoTests.cs

@@ -199,7 +199,7 @@ public void FlashFromInfo_RebootCommands_MappedCorrectly()
         [Fact]
         public void GetMaxDownloadSize_ClampsToSparseLimit()
         {
-            int originalLimit = FastbootDriver.SparseMaxDownloadSize;
+            long originalLimit = FastbootDriver.SparseMaxDownloadSize;
             try
             {
                 FastbootDriver.SparseMaxDownloadSize = 1024 * 1024 * 1024;

FirmwareKit.Comm.Fastboot/FastbootDriver.cs

@@ -143,7 +143,9 @@ public static LpMetadata ReadFromImageStream(Stream stream)
     /// Size of data to send in a single chunk (512KB for better WinUSB/Qualcomm compatibility)
     /// </summary>
     public static int OnceSendDataSize = 512 * 1024;
-    public static int SparseMaxDownloadSize = 1024 * 1024 * 1024; // 1GB default limit to match AOSP RESPARSE_LIMIT
+    // Host-side resparse limit. Keep this <= fastboot protocol DATA field max (uint32).
+    // A wider default avoids unnecessary sparse conversion for large images, reducing peak memory usage.
+    public static long SparseMaxDownloadSize = uint.MaxValue;
 
     private static readonly string[] PartitionPriority = {
     "preloader", "bootloader", "radio", "dram", "md1img", "xbl", "abl", "keystore",
@@ -341,12 +343,14 @@ public void EnsureUserspace()
             NotifyCurrentStep("Operation requires fastbootd, rebooting...");
             Reboot("fastboot").ThrowIfError();
 
-            System.Threading.Thread.Sleep(2000);
+            // Match AOSP behavior: allow disconnect to happen before attempting reconnect.
+            System.Threading.Thread.Sleep(1000);
+            NotifyCurrentStep("waiting for any device >");
 
             if (Transport is UsbDevice usbDev)
             {
                 var newUtil = WaitForDevice(UsbManager.GetAllDevices, usbDev.SerialNumber, 30);
-                if (newUtil == null) throw new Exception("Failed to reconnect to device after rebooting to fastbootd.");
+                if (newUtil == null) throw new Exception("Failed to boot into userspace fastboot; one or more components might be unbootable.");
 
                 this.Transport = newUtil.Transport;
             }
@@ -368,7 +372,7 @@ public void EnsureUserspace()
                     }
                     catch { System.Threading.Thread.Sleep(1000); }
                 }
-                if (!connected) throw new Exception("Failed to reconnect to TCP device after rebooting to fastbootd.");
+                if (!connected) throw new Exception("Failed to boot into userspace fastboot; one or more components might be unbootable.");
             }
             else if (Transport is UdpTransport udp)
             {
@@ -388,12 +392,18 @@ public void EnsureUserspace()
                     }
                     catch { System.Threading.Thread.Sleep(1000); }
                 }
-                if (!connected) throw new Exception("Failed to reconnect to UDP device after rebooting to fastbootd.");
+                if (!connected) throw new Exception("Failed to boot into userspace fastboot; one or more components might be unbootable.");
             }
             else
             {
                 throw new NotSupportedException("Automatic reboot to userspace is only supported for USB, TCP and UDP transports.");
             }
+
+            if (!IsUserspace())
+            {
+                throw new Exception("Failed to boot into userspace fastboot; one or more components might be unbootable.");
+            }
+
             _varCache.Clear();
         }
     }
@@ -481,8 +491,8 @@ public long GetMaxDownloadSize()
             return SparseMaxDownloadSize;
         }
 
-        // Match AOSP's host-side safeguard: never exceed the resparse limit.
-        return Math.Min(parsedSize, SparseMaxDownloadSize);
+        // Keep within protocol limits and the configurable host-side resparse limit.
+        return Math.Min(Math.Min(parsedSize, SparseMaxDownloadSize), uint.MaxValue);
     }
 
     /// <summary>

FirmwareKit.Comm.Fastboot/FirmwareKit.Comm.Fastboot.csproj

@@ -30,9 +30,8 @@
 
   <ItemGroup>
     <PackageReference Include="Crc32.NET" Version="1.2.0" />
-    <PackageReference Include="FirmwareKit.AVB" Version="1.0.0" />
     <PackageReference Include="FirmwareKit.Lp" Version="1.0.0" />
-    <PackageReference Include="FirmwareKit.Sparse" Version="1.0.0" />
+    <PackageReference Include="FirmwareKit.Sparse" Version="1.0.1" />
     <PackageReference Include="LibUsbDotNet" Version="3.0.167-alpha" />
   </ItemGroup>