From 6f2876fa66b41781f4fa3ad4352b7e81e1524bd6 Mon Sep 17 00:00:00 2001
From: Andreas Shimokawa <shimokawa@fsfe.org>
Date: Sun, 26 Nov 2023 00:22:37 +0100
Subject: [PATCH] Mi Watch 3 Lite: Fix firmware update

(not enabled yet)
---
 .../xiaomi/services/XiaomiDataUploadService.java  | 15 ++++++++++++---
 app/src/main/proto/xiaomi.proto                   |  3 ++-
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/xiaomi/services/XiaomiDataUploadService.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/xiaomi/services/XiaomiDataUploadService.java
index cffe771e7..9299fa81e 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/xiaomi/services/XiaomiDataUploadService.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/xiaomi/services/XiaomiDataUploadService.java
@@ -50,6 +50,8 @@ public class XiaomiDataUploadService extends AbstractXiaomiService {
     private byte currentType;
     private byte[] currentBytes;
 
+    private int chunkSize;
+
     public XiaomiDataUploadService(final XiaomiSupport support) {
         super(support);
     }
@@ -59,14 +61,21 @@ public class XiaomiDataUploadService extends AbstractXiaomiService {
         switch (cmd.getSubtype()) {
             case CMD_UPLOAD_START:
                 final XiaomiProto.DataUploadAck dataUploadAck = cmd.getDataUpload().getDataUploadAck();
-                LOG.debug("Got upload start, unknown2={}, unknown4={}", dataUploadAck.getUnknown2(), dataUploadAck.getUnknown4());
+                LOG.debug("Got upload start, unknown2={}, resumePosition={}", dataUploadAck.getUnknown2(), dataUploadAck.getResumePosition());
 
-                if (dataUploadAck.getUnknown2() != 0 || dataUploadAck.getUnknown4() != 0) {
+                if (dataUploadAck.getUnknown2() != 0 || dataUploadAck.getResumePosition() != 0) {
                     LOG.warn("Unexpected response");
                     this.currentType = 0;
                     this.currentBytes = null;
                     return;
                 }
+
+                if (dataUploadAck.hasChunkSize()) {
+                    chunkSize = dataUploadAck.getChunkSize();
+                } else {
+                    chunkSize = 2048;
+                }
+
                 doUpload(currentType, currentBytes);
                 return;
         }
@@ -131,7 +140,7 @@ public class XiaomiDataUploadService extends AbstractXiaomiService {
         buf2.putInt(CheckSums.getCRC32(buf1.array()));
 
         final byte[] payload = buf2.array();
-        final int partSize = 2044; // 2 + 2 at beginning of each for total and progress
+        final int partSize = chunkSize - 4; // 2 + 2 at beginning of each for total and progress
         final int totalParts = (int) Math.ceil(payload.length / (float) partSize);
 
         characteristic.setCallback(remainingParts -> {
diff --git a/app/src/main/proto/xiaomi.proto b/app/src/main/proto/xiaomi.proto
index 51a6934d0..fba30a3f4 100644
--- a/app/src/main/proto/xiaomi.proto
+++ b/app/src/main/proto/xiaomi.proto
@@ -869,5 +869,6 @@ message DataUploadRequest {
 message DataUploadAck {
   optional bytes md5sum = 1;
   optional uint32 unknown2 = 2; // 0
-  optional uint32 unknown4 = 4; // 0
+  optional uint32 resumePosition = 4;
+  optional uint32 chunkSize = 5; // 4096 on Redmi Watch 3 Active, Nonexistent on Mi Band 8
 }