blob: 7b2f0dd0924a47384e182c9b4c72efc8e1599eb5 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
<html devsite>
<head>
<title>OTA Updates</title>
<meta name="project_path" value="/_project.yaml" />
<meta name="book_path" value="/_book.yaml" />
</head>
<body>
<!--
Copyright 2017 The Android Open Source Project
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.
-->
<p>
Android devices in the field can receive and install over-the-air (OTA)
updates to the system and application software. This section describes
the structure of the update packages and the tools provided to build
them. It is intended for developers who want to make the OTA update
system work on new Android devices and those who are building update
packages for use with released devices. OTA updates are designed to
upgrade the underlying operating system and the read-only apps installed
on the system partition; these updates do <em>not</em> affect
applications installed by the user from Google Play.
</p>
<h2 id="ab_updates">A/B (seamless) system updates</h2>
<p>
Modern A/B devices have two copies of each partition, A and B. Devices
apply the update to the currently unused partition while the system is
running but idle. A/B devices do not need space to download the update
package because they can apply the update as they read it from the
network. This is called <em>streaming A/B</em>. A/B updates are also
known as <em>seamless updates</em>. For more information about OTA
updates for A/B devices, see
<a href="/devices/tech/ota/ab/index.html">A/B (Seamless) System
Updates
</a>.
</p>
<h2 id="nonab_updates">Non-A/B system updates</h2>
<p>
Older devices have a special recovery partition containing the software
needed to unpack a downloaded update package and apply the update to
the other partitions. For more information, see
<a href="/devices/tech/ota/nonab/index.html">Non-A/B System Updates
</a>.
</p>
</body>
</html>
|
