The following is directed at Samsung Galaxy S5s running custom ROMs and custom recovery environments only. The Galaxy S5’s internal storage has multiple partitions, each with its own separate image. For the sake of this discussion, we’ll divide the partitions into 2 groups: customized and stock.
Customized partitions are the ones you’ve put a custom image onto. For most devices running custom ROMs, that’s the /recovery – this is where TWRP, CWM, etc. live – and /system – where the actual (custom) Android phone OS lives – partitions.
Stock partitions are the partitions with unmodified OEM images. For most devices running custom ROMs, that’s every partition except /recovery and /system. Because some of these partitions contain firmware for the phone’s hardware components and said firmware was developed for a particular version of Android, it’s important to keep them updated. It isn’t too hard to see how, for example, pairing firmware designed for Android 4.4.2 with a custom Android 7.1.1 ROM could cause problems.
This guide will show you how to update as many of the stock partitions as possible without touching the customized partitions:
- Download and install 7-Zip.
- Download the latest stock firmware (where “firmware” in this sense means an archive containing images for all partitions) from SamMobile.You’ll need to search by your phone’s model number at that page.
- Decompress the archive from the above step. If you find it contains a .tar.md5 file; decompress that too.
- In the folder containing the extracted files, select the following:
- NON-HLOS.bin – This is the 4G LTE modem firmware.
- modem.bin – This is the 2G & 3G modem firmware.
- rpm.bin – This is the resource and power manager.
- sbl1.mbn – This is the secondary bootloader.
- tz.mbn – This is the trust zone.
- sdi.mbn – This contains transmission band info (?)
- aboot.mbn – This is the phone bootloader. SELECT THIS ONLY IF YOUR PHONE SHIPPED WITH AN UNLOCKED BOOTLOADER (i.e. DO NOT SELECT IT IF YOU’RE USING A VERIZON S5 AS YOU WILL RE-LOCK THE BOOTLOADER.)
- Follow Steps 6 to 11 here.
And that’s it. All your partitions will be safely updated without touching your custom ROM or custom recovery.