[UPDATE: Not Necessarily] Android 13 Devices Will Use Huawei's EROFS File System Format

UPDATE: It seems like Google changed its mind. EXT4 and F2FS will also be allowed, according to Mishaal Rahman.

ORIGINAL ARTICLE: All devices intending to launch with Android 13 or newer have to start using Huawei’s EROFS file system format, a new report has found. Short for Enhanced Read-Only File System, EROFS was created by Xiang Gao on behalf of Huawei a few years ago.

The EROFS file system format could help save storage space on Android 13 devices

Esper.io’s Mishaal Rahman has tracked and uncovered multiple commits over the past few months referring to the change. Google will likely discuss this aspect of Android 13 in detail at an upcoming event. Rahman claims the Pixel 7 will be the first smartphone to include this file system format later this year.

Android Police speculates that these changes could be reflected in the Android Compatibility Definition document. We expect to run into more details about this new Android 13 requirement as we inch closer to its release this fall.

When implemented, developers will have to use the EROFS file system format for read-only partitions. Failing to match this criterion would restrict manufacturers from accessing Google’s services, including the Play Store.

Leveraging the EROFS file system for read-only partitions makes sense from an efficiency perspective. Moreover, some partitions on Android are read-only anyway, so compressing them using the more efficient EROFS file system format is the logical next step for Android. Thanks to this format, the system will take up lesser storage, while update downloads could become significantly faster.

OPPO and Xiaomi already use the EROFS file system format in some capacity

According to Rahman, devices stand to save up to 800MB of space if they build a Cuttlefish virtual Android device image using EROFS. Furthermore, this could also mean a reduction in the OTA update size. According to the research paper submitted by Xiang Gao and other researchers in 2019, EROFS can reduce boot times of “real-world applications” by up to 22.9%.

Interestingly, EROFS also seems to pip the existing Android EXT4 file system in non-compressed applications. “Compared with Ext4 and F2FS without compression support, EROFS always performs comparably with and even outperforms them,” the researchers said. Google has enabled EROFS support among some of its internal tools over the past few months. Meanwhile, brands like Xiaomi and OPPO already use Huawei’s file system format in some form.