System Partitions: All you need to know!

There are many partitions in your device that make up the firmware. The partitions in your device include /system, /vendor, /product, /media, /boot etc. These partitions can be read and written. You can only write a partition if your system is mounted Read/Write (RW). If your device is mounted Read Only (RO) which is by default, the only way to write any sensitive partition is through fastboot.

Why would i want to write a partition?

To write a partition is basically flashing that partition either to fix it, or to change it's contents. Some use case scenarios are

• Flashing system.img
• Flashing Vendor.img
• Flashing boot.img

The list goes on. Partitions have sizes and if the file/.img you wish to flash is bigger than the allocated size, it will not fit and the operation will automatically aborted. You may face this issue with /system especially when trying to flash a Generic System Image (GSI). Primarily, the reason for meddling with partitions is to fix them by reflashing.

One of the most uses of this is /vendor mostly when you reflash your firmware and you get the "can't connect to camera" error in your camera. Reflashing /vendor often fixes this issue, this is not the only solution, but it's much faster to try and can be done in fastbootd.