What is Fastboot exactly? - Android Q&A, Help & Troubleshooting

So, if I completely wipe the storage of an android device, would I still be able to enter the Fastboot?
Is fastboot the same thing like bios? Where is fastboot-programm storaged?
Can I actually break the fastboot funktion somehow?
I also would be thankful if you just give me some good links. Thanks.

@GoFurthAndDie
1.
The BIOS of an Android device is the BOOTLOADER.
2.
In Android, FASTBOOT is a special diagnostic and engineering protocol that you can boot your Android device into. While in FASTBOOT, you can modify the file system images from a computer over a USB connection (AKA ADB ).
FASTBOOT is three different things with the same name:
A protocol for communication between your phone hardware and a computer
A software that runs on the phone when in fastboot mode
The executable file on the computer you use to make them talk to each other
3.
FASTBOOT is a Windows app.

jwoegerbauer said:
@GoFurthAndDie
1.
The BIOS of an Android device is the BOOTLOADER.
2.
In Android, FASTBOOT is a special diagnostic and engineering protocol that you can boot your Android device into. While in FASTBOOT, you can modify the file system images from a computer over a USB connection (AKA ADB ).
FASTBOOT is three different things with the same name:
A software that runs on the phone when in fastboot mode
The executable file on the computer you use to make them talk to each other
3.
FASTBOOT is a Windows app.
Click to expand...
Click to collapse
First thing, thank you very much for your answers.
Now I have an other question: if I use Fastboot to boot up TWRP and then use TWRP to wipe all data and all partitions from the intern storage of my android device and reboot it without flash any new ROMs (no /boot partition and all the other partitions), then my smartphone won't funktion any and won't be able to get into the fastboot mode on my phone.
If this happens, what could I do to make this smartphone functional again?

@GoFurthAndDie
Run
Code:
fastboot boot <<twrp.img>>
where <<twrp.img>> is replaced with your TWRP image name. This will boot you back into TWRP and should allow you to use TWRP to install a stock recovery and system partition.
Alternately, run
Code:
fastboot flash recovery <<twrp.img>>
to flash TWRP back to your recovery, and boot into recovery normally.

Related

[Q]All that bootloader jargon?

I was trying to understand what is fastboot. And then I got caught into all that bootloader jargon and couldn't differentiate one from the other. So I have a few questions. If someone could make me understand this stuff...I would be really grateful. Thanx guaranteed:laugh:
1. What is fastboot? When I run fastboot commands through cmd...I get <waiting for device>.
2. How to get into fastboot mode...should I boot into bootloader? How?....I possess a Samsung Galaxy R...very similar to the galaxy s2
3. I know how to get into recovery...I'm rooted and have a custom recovery CWM. Is recovery same as bootloader?
4. Then what is download mode....how is it different from bootloader mode or recovery mode?
5. I tried running fastboot commands through cmd by entering recovery and download mode...but got the same message as in point 1. Whats wrong???
The-Droidster said:
I was trying to understand what is fastboot. And then I got caught into all that bootloader jargon and couldn't differentiate one from the other. So I have a few questions. If someone could make me understand this stuff...I would be really grateful. Thanx guaranteed:laugh:
1. What is fastboot? When I run fastboot commands through cmd...I get <waiting for device>.
2. How to get into fastboot mode...should I boot into bootloader? How?....I possess a Samsung Galaxy R...very similar to the galaxy s2
3. I know how to get into recovery...I'm rooted and have a custom recovery CWM. Is recovery same as bootloader?
4. Then what is download mode....how is it different from bootloader mode or recovery mode?
5. I tried running fastboot commands through cmd by entering recovery and download mode...but got the same message as in point 1. Whats wrong???
Click to expand...
Click to collapse
Answers:
1) [Q] What is Fastboot?
[A] Fastboot is a command line tool used to directly flash the filesystem in Android devices from a host via USB. It allows flashing of unsigned partition images. It is disabled in production devices since USB support has been disabled in the bootloader.
2) [Q] How to get into Fastboot Mode?
[A] I have no idea on your specific device, but I would imagine a little Google'ing and you could find the answer. I'm sure it's like any other device: a combination of certian button presses upon reboot or at boot.
3) [Q] Is recovery the same as bootloader?
[A] No. The bootloader, in literal terms, is code that is executed before any Operating System starts to run. The concept of bootloaders is universal to virtually all Operating systems that inculcates operating systems on your PC, laptop, smartphones, and other such devices. Bootloaders basically package the instructions to boot operating system kernel and most of them also have their own debugging or modification environment. As the bootloader kicks off before any piece of software on your device, it makes it extremely processor specific and every motherboard has it’s own bootloader. This is one reason that all Android phones have different Custom ROMS developed due to high variance of processing hardware present on the device.
Your recovery is, as in Android, a recovery that refers to the dedicated, bootable partition that has the recovery console installed. A combination of key presses (or instructions from a command line) will boot your phone to recovery, where you can find tools to help repair (recover) your installation as well as install official OS updates. Because Android is open and has the recovery source code available, building a customized version with more and different options is relatively easy as well.
4) [Q] What is download mode?
[A] Download mode is for when you want to flash a new firmware using something like odin, If you update your firmware using kies, kies will automatically put the phone into download mode, if you use odin you have to put the phone into download mode yourself.
5) [Q] I tried running fastboot commands through cmd by entering recovery and download mode...but got the same message as in point 1. Whats wrong???
[A] You're confused as to what the difference is bewteen fastboot and recovery mode are. Hopfeuly, this gave some clarifiaction...

[Q] Copying files from Phone to PC using fastboot?

Short version - is it possible to copy files from my phone to my PC using fastboot (or perhaps adb)? The cyanogenmod WIKI for fastboot, among others, imply that you can (under the section Examples -> Manual Nandroid Restore it says "Make a Nandroid backup, and copy the folder off your SD card to your desktop."). Sorry I'm not allowed to post the link due to being a new user, but this is what it says:
"Make a Nandroid backup, and copy the folder off your SD card to your desktop.
cd ~/Desktop/path/to/backup/
fastboot flash userdata data.img
fastboot flash system system.img
fastboot flash boot boot.img
fastboot reboot"
If it is possible, is "flash" the correct command to be using? The description of the flash command when you run "fastroot help" implies it writes data to the phone, not from the phone to the PC... Unfortunately almost everything I search for around the flash command is examples showing how to load ROMs etc, I can't seem to find anything else that points to it being used to backup data...
[UPDATE] - From what I understand you can't copy files off the phone using fastboot commands, but can using adb - so a few questions:
- Does anyone know why adb wouldn't see my device (when I run "adb devices") but fastboot does (note that I'm on the fastboot screen)?
- Does adb require debugging mode to be on?
[UPDATE-2] - Still can't get adb working, suspect it's because USB debugging isn't enabled (though not sure how I can check?). I did try using fastboot to erase the /cache partition in case the lockout data was stored in there - but this didn't work unfortunately. Looking likely I'll just have to wipe it with fastboot oem unlock
Long version / background info:
Using a Samsung Nexus S with Android 4.1
The other night someone down the pub decided to try to unlock my phone, and apparently got the pattern wrong so many times it's now requiring me to enter my Google account details.
Fine, I enter the username / pass, only it says they're wrong - I know they're correct because I've just confirmed they are by logging into Gmail. It says they're incorrect so quickly that I suspect it's not even connecting to the web to check. The icons at the top imply there is signal, but it looks as though 3G / data is off, and there's no WiFi icon even though I'm sat next to my wireless router. I can't find any way to re-enable WiFi / 3G without first unlocking the phone - which requires a net connection. So I got into Fastboot Mode and selected Recovery and the device looks as though it's doing something (deleting all user data I assumed), but when it starts up it's exactly the same - which implies the user data hasn't been erased.
Then I installed fastboot, and the drivers for the Nexus S.
When I run "fastboot devices" I can see the phone listed, however bizarrely "adb devices" lists nothing.
"fastboot oem unlock" seems to work (the phone prompts me to confirm I want to give root access & delete all user data). I haven't done this yet as I want to see if I can save my data somehow using adb or fastboot commands.
For adb to work, your phone must be booted and USB debugging enabled. In your current situation, as far as I know, a factory reset is the only option.
The phone is either in ADB mode or in Fastboot mode. It can never be in both ADB and Fastboot at the same time. ADB requires the phone is up and running, Fastboot requires the phone is in bootloader mode. ADB requires debugging turned on.
If you unlock your bootloader, you can boot the phone using fastboot and your own recovery image using "fastboot boot myrecovery.img" (notice, no flash keyword here). Booting your device with this recovery image, you can do whatever you like and the image permits, e.g. running ADB and copying files. You'll need this recovery image, though.
Thanks, I did try fastboot with a recovery image, but it currently doesn't work because I need to unlock the bootloader (which will wipe all data anyway). Sounds like I will need to just wipe it
kuisma said:
The phone is either in ADB mode or in Fastboot mode. It can never be in both ADB and Fastboot at the same time. ADB requires the phone is up and running, Fastboot requires the phone is in bootloader mode. ADB requires debugging turned on.
If you unlock your bootloader, you can boot the phone using fastboot and your own recovery image using "fastboot boot myrecovery.img" (notice, no flash keyword here). Booting your device with this recovery image, you can do whatever you like and the image permits, e.g. running ADB and copying files. You'll need this recovery image, though.
Click to expand...
Click to collapse
Facing same issue.
Is there anyway so I could copy userdata.img to my pc and then delete gesture.key file (I am running Lollipop) with NO USB DEBUGGING ON in Fastboot mode.
I have gone through "unpacking and packing .img files"http://forum.xda-developers.com/galaxy-s2/general/ref-unpacking-repacking-stock-rom-img-t1081239
But it is out of my knowledge range can anyone get through it and explain me the same.
Hi! I am in the same situation... ADB not working, only fastboot... Any way to save my data? Do I need to unlock bootloader to install a stock recovery? Thank you!
Hi - I am in exactly same situation as well. I am using Oneplus 8t. Any help is greatly appreciated. thanks

[Help] can't install custom recovery on Lenovo Vibe C at all!

Hello
A newbie here ...
My new phone "Lenovo Vibe C (A2020)" does not allow me to install any kind of custom recovery on it, I tried the following methods ...
1- SP Flash Tool: doesn't detect my phone at all, even after installing all drivers (Qualcomm, MTK, Etc ,,, ).
2- Adb and fastboot: whenever I try to flash a recovery, it only shows (waiting for a device) command, even after being detected by "adb devices" command, and showing device ID.
3- flashing apps: I used flashify and thrasher, at the beginning they both show a successful flashing process, up until rebooting to recovery, then only shows "Lenovo" logo for a second right before turning the phone off.
that's what i did, any help would be appreciated.
Note: the phone isn't even indexed in the site's database ... I wonder why!
You should unlock the bootloader first after rooting your device
Hello there. I do hope that you can still boot your device normally. If you can, please do make a backup of your rom.
(a) Download and install the latest driver for your device
(b) Download the latest adb and fastboot tool (I recommend Minimal ADB and Fastboot)
(c) Download the custom recovery image. Save/copy it on the root directory of your ADB and Fastboot folder.
(d) In your device, go to settings > developer > enable oem unlocking and usb debugging (which is I guess you already did).
(e) Now open your terminal/cmd: adb reboot bootloader (this will boot your device in fastboot)
(f) In terminal/cmd: fastboot oem unlock (or fastboot oem unlock-go)
(g) Now flash the custom recovery: fastboot flash recovery "recovery.img"
***I suggest you try first if the custom recovery image works: fastboot boot recovery.img
(h) Reboot into recovery and check if it works.
Ospider said:
Hello
A newbie here ...
My new phone "Lenovo Vibe C (A2020)" does not allow me to install any kind of custom recovery on it, I tried the following methods ...
1- SP Flash Tool: doesn't detect my phone at all, even after installing all drivers (Qualcomm, MTK, Etc ,,, ).
2- Adb and fastboot: whenever I try to flash a recovery, it only shows (waiting for a device) command, even after being detected by "adb devices" command, and showing device ID.
3- flashing apps: I used flashify and thrasher, at the beginning they both show a successful flashing process, up until rebooting to recovery, then only shows "Lenovo" logo for a second right before turning the phone off.
that's what i did, any help would be appreciated.
Note: the phone isn't even indexed in the site's database ... I wonder why!
Click to expand...
Click to collapse
Check my thread for custom marshmallow rom and twrp recovery .
https://forum.xda-developers.com/android/general/bliss-rom-lenovo-vibe-c-a2020a40-t3567812
rolland.arriza said:
Hello there. I do hope that you can still boot your device normally. If you can, please do make a backup of your rom.
(a) Download and install the latest driver for your device
(b) Download the latest adb and fastboot tool (I recommend Minimal ADB and Fastboot)
(c) Download the custom recovery image. Save/copy it on the root directory of your ADB and Fastboot folder.
(d) In your device, go to settings > developer > enable oem unlocking and usb debugging (which is I guess you already did).
(e) Now open your terminal/cmd: adb reboot bootloader (this will boot your device in fastboot)
(f) In terminal/cmd: fastboot oem unlock (or fastboot oem unlock-go)
(g) Now flash the custom recovery: fastboot flash recovery "recovery.img"
***I suggest you try first if the custom recovery image works: fastboot boot recovery.img
(h) Reboot into recovery and check if it works.
Click to expand...
Click to collapse
But how about a person WITHOUT PC? Including me.

Le eco le pro 3 (x727) freeze cannot start

My le eco le pro 3, during a normal day, stopped working.
If i try to turn it on i see the "LeEco powered by android" and after 10 seconds it turns off with a blue led.
I can not access the recovery mode, only the fastboot mode.
What fastboot command do i have to do to fix this? :crying:
If you can reach fastboot that is great already, i dont know if they bundle their devices with a recovery so you'll need to find a recovery for your device (quick google search, look for TWRP)
Also grab the drivers for your phone so you'll be able to write the recovery you downloaded.
Download the Google Universal ADB + Fastboot package (the 10 seconds installer)
Once everything is done, you'll need to go to the folder containing ADB and Fastboot with a command prompt
In the same folder you put the downloaded recovery. Put your phone in recovery mode, plug it, and type in the cmd : fastboot devices
If it recognize something you are good to go, you type fastboot flash recovery recoveryname.img
Then lookup for a Rom, i'm sure there is plenty of it, you'll flash the Rom either with sideload or if you have TWRP via Transfer
Gtahero74 said:
If you can reach fastboot that is great already, i dont know if they bundle their devices with a recovery so you'll need to find a recovery for your device (quick google search, look for TWRP)
Also grab the drivers for your phone so you'll be able to write the recovery you downloaded.
Download the Google Universal ADB + Fastboot package (the 10 seconds installer)
Once everything is done, you'll need to go to the folder containing ADB and Fastboot with a command prompt
In the same folder you put the downloaded recovery. Put your phone in recovery mode, plug it, and type in the cmd : fastboot devices
If it recognize something you are good to go, you type fastboot flash recovery recoveryname.img
Then lookup for a Rom, i'm sure there is plenty of it, you'll flash the Rom either with sideload or if you have TWRP via Transfer
Click to expand...
Click to collapse
Thank you so much.
I have type c broken, so i cannot plug it into my pc (i have found replacement).
I found this guide https://forum.xda-developers.com/le-pro3/how-to/flashing-guide-roundup-leeco-le-pro-3-t3511901
If i don't want to root, do i have to unlock the bootloader anyway?
It might be a stupid question, but I do not know much about this.
Yeah you will need to unlock the bootloader in order to flash a new rom
But roms aren't rooted so you can relock your bootloader after

TMobile REVVL XT1965-T?

I have this phone and now it wont boot. Im thinking there is no OS to boot. It tries and says DM varity disabled at top of screen then says software cant be checked for corruption /bootloader unlocked. When in bootloader there is no recovery to boot into as well when plugged into desktop . ADB devices command is not seeing it. So my question is where do I start to install recovery and make PC (adb/fastboot) recognize device. If I could get adb to identify device shouldn't I be able to fastboot boot (twrp-disc.img) then flash twrp.zip then reboot bootloader and flash factory ROM and kernel or custom? Hate if I sound like a noob im learning all I can. Any help is greatly appreciated!
ADB, Fastboot & Recovery are 3 completely things independent from each other:
ADB program deals with Android OS ( folders / files / settings )
Fastboot program deals with device's bootloader
Recovery is a special bootable partition on device, which contains a recovery application installed in it
If
Code:
adb devices
doesn't show you a connected "device" then either USB debugging isnt enabled or Android OS isn't accessable at all or Android's USB service isn't set to "adb"
If
Code:
fastboot devices
doesn't show you device's mode as "fastboot" then device's bootloader isn't accessable at all.
Back to your "issue", well, it's NORMAL, starting from Android Marshmallow on ALL devices with an unlocked bootloader & disabled "dm-verity" will boot with those warning, so nothing to worry about, and , at the moment it's not possibile to remove those warnings.
When Fastboot is working, then you should be able to boot device into a Custom Recovery, of course only if that is at 100% suitable to the device.

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