Awesome

ISD-R Access Provider

Introduction

You just want to study how eSIM works with consumer-model described GSMA SGP.21 and SGP.22, but cannot find a good way to get a plug-in (4FF/nano) eSIM card, right? I also sent queries to some eSIM service providres and got the same responses that such a product is not available right now (maybe in the future also). Though I wanted to prepare a development/study environment like the following figure 1, I gave it up for now. Then, I came up with an easy, not cool but possible compromise solution in the figure 2 below.

This application contains a tiny content provider for communicating with ISD-R in eSIM soldered on Android device. Do you have a Google Pixel 4? If you do not need to have it for daily use, you can make it rooted and flash the recent version of Google/AOSP user-debug software image in order to utilize it as a bit bigger eSIM-like device. See your phone again. It is not a phone but an eSIM-like something to you, okay?

Usage

It is a simple content provider interface through adb command. Here is an example of a pair of command and response. The ES10x command sent via this interface is ProfileInfoListRequest 'BF2D' and the requested data objects are profileState '9F70', profileName '92', profileClass '95' and notificationConfigurationInfo 'B6'.

$ adb shell content query --uri content://com.github.cheeriotb.isdrap.provider/store/BF2D075C059F709295B6
Row: 0 response=BF2D7DA07BE31D9F7001009214416E726974737520546573742050726F66696C65950100E35A9F700100920349494A950102B64C302480020410811E534D2D56342D3033332D412D47544D2E50522E474F2D4553494D2E434F4D302480020780811E534D2D56342D3033332D412D47544D2E50522E474F2D4553494D2E434F4D9000

It is a bit hard to interpret ProfileInfoListResponse responded from ISD-R manually, so please refer to the following table. You or your application software just has to run the adb command with your DER-encoded ES10x command data, then receive and interpret response from ISD-R in accordance with the GSMA standard specification. The APDU header part is added by the content provider and ISD-R is also automatically selected internally.

The content provider and eSIM are not always ready to receive new request. If any kind of temporary failure is indicated in the responded status word, please try to send the same ES10x command several times at a certain interval.

Dependency

It is necessary to push an APK and a permission file to the system partition, so your eSIM-capable Android phone must be rooted. And also, any kind of LPA implementation should not be in the system because only one application can have a right to talk with ISD-R in the system. This application should have the right. In order to satisfy that, it is the easiest way to flash a recent version of Google/AOSP user-debug binary by using Android Flash Tool. See the next section.

Note that this application is well adapted to Google Pixel 4 that I have. My assumption is that we can use this for newer products like Google Pixel 5 without any code change, but not tested.

Setup

First, you have to prepare a rooted Android device. If your phone is a Google's phone product, please try Android Flash Tool (https://flash.android.com/) for flashing a recent version of Google/AOSP user-debug build.

Then, please push an APK and the permission file com.github.cheeriotb.isdrap.xml to the system partition of your rooted Android device. Do not forget to make the folder 'IsdrAccessProvider' under /system/priv-app in advance.

$ adb root
$ adb remount
$ adb push app-debug.apk /system/priv-app/IsdrAccessProvider
$ adb push com.github.cheeriotb.isdrap.xml /system/etc/permissions
$ adb reboot

Licence

This software is released under the MIT License, see LICENSE.

Author

Cheerio (cheerio.the.bear@gmail.com)

References

• GSMA
  • SGP.22 v2.2.2
• GlobalPlatform
  • Card Specification v2.3.1