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[INFO] ANDROID DEVICE PARTITIONS and FILESYSTEMS

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By mirfatif, Senior Member on 8th April 2017, 10:37 PM
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23rd April 2019, 08:21 PM |#41  
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It's amazing to me how many people will post asking for help and not even mention what kind of device they have.

---------- Post added at 07:21 PM ---------- Previous post was at 07:15 PM ----------

Quote:
Originally Posted by novosti

After firmware flashing, after reboot i got error :
security check fail : modem

and booting stop with message "Security Error : This phone has been flashed with unauthorized software".

I tried "combine file flash" - but it's got me same error, after reboot it's stack ...
with error :

SS DRX
Subsystem Crashed : MODEM

You probably tried to flash firmware that had included modem firmware below the phones verified boot count. If the process gave you "secure check fail: modem", than it stopped flashing at that point and the rest of the room wasn't installed. Probably why you don't have product code, that's in the csc image and is flashed after modem.

Tldr;
ROM version is too old, use a newer one that supports your bootloader revision. Bootloader revision can be checked in filename of firmware. It's 5 number from the right at end of file name. IE:
G950USQU5DSC1
Bootloader revision is 5.
Sometimes firmwares with the correct bootloader revision will fail the verified boot check on other parts besides the bootloader. Only option is to try a newer one.
28th June 2019, 11:37 PM |#42  
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Quote:
Originally Posted by mirfatif


SYSTEM - ROM / OS
Contains system applications and libraries that have AOSP source code. During normal operation, this partition is mounted read-only; its contents change only during an OTA update or when flashing a new OS. Most ROM's don't allow root level (Admin rights in Windows) access by default. So, "rooting" is required to modify the contents of this partition. This is the actual User Interface we use on our phone i.e. system apps are installed on this partition on /system/app directory. Another important directory is /system/bin which contains executable binaries to perform each and every action by OS in background (as daemons) or by user in shell (bash) scripts or CLI (command line interface). These are native binaries (developed in C / C++ mostly) as opposed to Android apps which are developed in Java. A minimal form of Linux commands is also included in AOSP as toolbox or toybox (or user can add busybox or individual static binaries). /system/lib directory contains native libraries (shared by applications commonly) with .so extensions just like .dll on Windows.

USERDATA
User applications are installed in different folders under /data. Apps data (user and system) is stored in /data/data. User personal data and some apps data is stored in /data/media. /data/media is also emulated as internal SDCard at /storage/emulated and symlinked at /sdcard. Personalized and apps settings are also stored in this partition. A folder /data/dalvik contains, in simple words, extracted apps to boost loading process. Java bytecode of Android apps is converted to executable code (.odex) by Dalvik Virtual Machine, separate instance of which is launched by zygote (an Android init daemon) for every app.
This partition is not normally touched by the OTA update process. A Factory Reset wipes this partition, normally excluding /data/media i.e. personal data.
When you do a factory reset (AKA: wipe, hard reset, factory wipe, etc.), you are erasing the /data and /cache partitions. Note that a factory reset does NOT put your phone back to its factory state from an OS standpoint. OS upgrades will stay because the OS lives in /system, and that is not touched during a factory reset. So it's not a factory reset. It's a factory DATA reset actually.

Hello, I am trying to resize my partition table, I reduced the cache and fota partitions and want to add the free memory to RAM.

But I don't see anything in your write up that talks about where RAM comes from. The two largest partitions on my device are the system and userdata: userdata is obviously internal storage. While moving the free space to /system add to the RAM?

Or is this impossible and I should just add the resized partitions back to userdata?
29th June 2019, 02:20 PM |#43  
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Quote:
Originally Posted by Teracotta

Hello, I am trying to resize my partition table, I reduced the cache and fota partitions and want to add the free memory to RAM.

But I don't see anything in your write up that talks about where RAM comes from. The two largest partitions on my device are the system and userdata: userdata is obviously internal storage. While moving the free space to /system add to the RAM?

Or is this impossible and I should just add the resized partitions back to userdata?

It's impossible
29th June 2019, 09:36 PM |#44  
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Quote:
Originally Posted by Teracotta

Hello, I am trying to resize my partition table, I reduced the cache and fota partitions and want to add the free memory to RAM.

But I don't see anything in your write up that talks about where RAM comes from. The two largest partitions on my device are the system and userdata: userdata is obviously internal storage. While moving the free space to /system add to the RAM?

Or is this impossible and I should just add the resized partitions back to userdata?

RAM is memory and requires power to store data. Storage does not. Ram stores the data your phone is currently using so the processor can access it quickly because it is much faster than storage. They are very different from each other and can't be increased.
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30th June 2019, 11:48 PM |#45  
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Quote:
Originally Posted by Teracotta

Hello, I am trying to resize my partition table, I reduced the cache and fota partitions and want to add the free memory to RAM.

But I don't see anything in your write up that talks about where RAM comes from.

What I have written is completely about Embedded MultiMedia Controller (eMMC) which is a kind of flash memory; a low grade version of SSDs and high grade version of SD cards or USB sticks.
RAM is a totally different thing, it's volatile and very high speed memory. eMMC is persistent memory and relatively very slow.

On embedded devices, both eMMC and RAM are part of same unit usualy a Multi-Chip Package (MCP) from the same vendor, integrated inside a System on Chip (SoC) module.
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2nd August 2019, 01:55 PM |#46  
Thank you for all the information. So glad i could find such comprehensive collection on this topic.

I have a question that i really hope i can get an answer for: where are the NV items stored?
By NV items i meant the non-vollatile settings (like LTE band stuff) you can modify through usb diag mode and Qualcomm's QPST and QXDM tools.

I messed up the LTE setting on my xiaomi mi 9t and now the diag port is not responding correctly anymore. So i am try really hard to revert the change i did on the NV items without using the diag mode.

Any input would be much appreciated.
Thank you!
4th August 2019, 02:18 AM |#47  
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Quote:
Originally Posted by kezzuki

Thank you for all the information. So glad i could find such comprehensive collection on this topic.

I have a question that i really hope i can get an answer for: where are the NV items stored?
By NV items i meant the non-vollatile settings (like LTE band stuff) you can modify through usb diag mode and Qualcomm's QPST and QXDM tools.

I messed up the LTE setting on my xiaomi mi 9t and now the diag port is not responding correctly anymore. So i am try really hard to revert the change i did on the NV items without using the diag mode.

Any input would be much appreciated.
Thank you!

It should be in modem or radio.
4th August 2019, 03:09 AM |#48  
Quote:
Originally Posted by SnowFuhrer

It should be in modem or radio.

Probably not, cus i flashed those partitions and the wrong settings were not reset. lol
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4th August 2019, 03:20 AM |#49  
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Quote:
Originally Posted by kezzuki

Probably not, cus i flashed those partitions and the wrong settings were not reset. lol

Hmm, what are the options then? 🤔 Maybe EFS?
4th August 2019, 04:34 AM |#50  
Quote:
Originally Posted by SnowFuhrer

Hmm, what are the options then? 🤔 Maybe EFS?

Probably EFS but in my understanding EFS is a collection of a few partions or part of those partitions.

My full story is here:
https://forum.xda-developers.com/mi-...-mode-t3953983

Quick recap, i have even tried EDL mode and that didnt fix it lol
6th September 2019, 07:50 AM |#51  
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I have a problem with system partition(not internal storage). The problem is that it shows low space in system partition in twrp( 60 mb left) and i cant use some apps like GL Tools as they are installed in system partition. Can we resize system partition? Or something similar but without uninstalling system apps so that OTAs will not stop.
My device is redmi note 5 pro(whyred)
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android partitions, data partition, partition, system partition

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