What Is An OEM Partition?
An OEM partition is also known as ‘MSDM’ (Microsoft Diagnostics and Recovery Toolset) partition or simply ‘Recovery Partition’, It stores data like tools & diagnostics used by manufacturers during manufacturing stage for repairing purpose which are required in some cases to recover your tablet/phone after facing any issue with OS . It’s always located at the very beginning of the disk i.e. before C: drive(within 200MB) .
How Can We Identify OEM Partitions?
MSDM partitions or Recovery Partitions are generally not visible through Windows Explorer, diskmgmt.msc and other similar tools because they don’t contain any data and are only designed to store tools for recovery purposes. So we need a 3rd party tool called ‘Minitool Partition Wizard’ that can show you the list of all partitions on your hard drive as well as android device.
2nd Way to identify is by booting into recovery mode & then check whether it has the option to factory reset/wipe cache or not as those options will never be available in stock recovery mode unless there’s a separate partition for recovery tools. You can use Minitool Partition Wizard or “Shift + refresh” keys (in case of Windows 8 and above) to boot into Recovery mode on any Windows OS .
3rd Way is by using an android app called ‘Android System Info’, This app shows you the list of
all partitions including MSDM partition as well as size, type & location of each partition. So you can easily identify your device’s OEM partition (MSDM).
What does OEM Partition do
OEM Partitions are mainly used to store data required for booting into recovery mode or flashing firmware images such as ‘boot.img’, ‘recovery.img’ and other partitions related to them like ‘fota_start.bin’ & many more which is needed in some cases when you want to unbrick your android device without flashing a stock firmware image via fastboot/odin mode .
How Can We Use OEM Partition
OEM Partitions are generally used to install Stock Firmware, Custom Recovery images through ADB sideload method as this method doesn’t require root privileges but it can be done only when your device is detected by ADB Sideload .That custom recovery image file contains a script which automatically launches the stock recovery image on installation of stock firmware as some devices don’t have any such option in their stock recovery mode so we need some other way to launch the custom recovery , hence installing via ADB sideload requires an extra OEM partition to store those tools.
NEVER try to delete, modify or format any OEM partition as it might cause your device to be unbootable & there’s no way to recover your android device unless you have a stock firmware image for that type of android device.
How to Create OEM Partition
Easiest Method to Create OEM Partition without Root
You can create OEM partition on any android device running Android 4.4 Kitkat and above without rooting your android device but you must have a custom recovery image installed on your device as we’ll be using it to format the disk with one command line which will automatically create an MSDM (OEM Partition) of size 100MB just after ‘system’ partition, So that next time when you boot into recovery mode it will show you an option to factory reset/wipe cache before doing anything else .
To do this go to TWRP recovery & click on “Wipe” > Select Disk and select your android device, It’ll show you only two partitions (system & cache) due to lack of free space it can’t list all the partition available on your android device, Now select ‘Partition’ option from TWRP main menu & then select “New” > enter “100MB” as Partition size > set As File System: Auto and Format Options: Data , Click on Advanced button under Format Option and check off both Erase and Force to be formatted options. Click on Ok and swipe left-to-right to confirm the formatting process, wait until it completes. Click on the Reboot system option when it finishes .
That’s it now you can check whether an MSDM partition is created or not by following the above mentioned way.
OEM Partition is needed for installation of stock firmware images through ADB side load which requires an extra 100MB partition to store custom recovery image files. If you are facing trouble modifying or formatting OEM partitions then don’t try it on your own as that will make your device unbootable.
To add more to this, you can add an OEM partition only when your android device has got free space. So if someone tries to create one on their own without having any unallocated/free memory available then the OS will automatically shrink one of the existing partitions & make some free space so that it can create an extra OEM Partition for ADB Sideload purpose. It’s all about Android Systems.
We hope The Above Mentioned Article gave you a Great Insight of OEM Partitions and their creation.