[protocol] Fix console read request sizing

protocol/BUILD

@@ -558,6 +558,18 @@ cc_library(
     ],
 )
 
+cc_test(
+    name = "console_test",
+    srcs = ["console_test.cc"],
+    deps = [
+        ":console",
+        "//protocol/test:libhoth_device_mock",
+        "//transports:libhoth_device",
+        "@googletest//:gtest",
+        "@googletest//:gtest_main",
+    ],
+)
+
 
 cc_library(
     name = "dfu_hostcmd",

protocol/console.c

@@ -91,7 +91,7 @@ libhoth_error libhoth_read_console(struct libhoth_device* dev, int fd,
   struct hoth_channel_read_request req = {
       .channel_id = channel_id,
       .offset = *offset,
-      .size = HOTH_FIFO_MAX_REQUEST_SIZE -
+      .size = HOTH_FIFO_MAX_REQUEST_SIZE - sizeof(struct hoth_host_response) -
               sizeof(struct hoth_channel_read_response),
       .timeout_us = 10000,
   };

protocol/console_test.cc

@@ -0,0 +1,56 @@
+// Copyright 2026 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "console.h"
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+#include <unistd.h>
+
+#include <cstdint>
+
+#include "test/libhoth_device_mock.h"
+
+using ::testing::_;
+using ::testing::DoAll;
+using ::testing::Return;
+
+constexpr uint32_t kCmdChannelRead =
+    HOTH_CMD_BOARD_SPECIFIC_BASE + HOTH_PRV_CMD_HOTH_CHANNEL_READ;
+
+bool CheckReadSize(const void* data) {
+  const auto* req = static_cast<const struct hoth_channel_read_request*>(data);
+  return req->size == 1012;
+}
+
+TEST_F(LibHothTest, read_console_test) {
+  EXPECT_CALL(mock_,
+              send(_, UsesCommandWithData(kCmdChannelRead, CheckReadSize), _))
+      .WillOnce(Return(LIBHOTH_OK));
+
+  struct {
+    struct hoth_channel_read_response hdr;
+    uint8_t data[1012];
+  } fake_response = {};
+  fake_response.hdr.offset = 100;
+
+  EXPECT_CALL(mock_, receive)
+      .WillOnce(DoAll(CopyResp(&fake_response, sizeof(fake_response)),
+                      Return(LIBHOTH_OK)));
+
+  uint32_t offset = 100;
+  EXPECT_EQ(libhoth_read_console(&hoth_dev_, STDOUT_FILENO, false, 0, &offset),
+            HOTH_SUCCESS);
+  EXPECT_EQ(offset, 100 + 1012);
+}