Introduction
Other bootable modes
Leaving other bootable modes
Hardware buttons
What is a stock ROM and how do I get one?
What is a Custom recovery and where does it go?
What is Teamwin?
Now you are ready to study the software
Easy Installer
Now you are prepared to commit
Do I have to do a factory reset before I start?
Your first boot into TWRP
Use the eWiki
OEM Unlock - toggle now missing
Introduction
You have never changed the ROM on a phone, you have a Samsung phone and are are contemplating a move to /e/. This article hopes to be a low level primer to help you understand some of the things you have to work with. For an easy journey, with your enquiring mind, invest a bit of time increasing your depth of knowledge and enjoy a new learning experience.
This is written in very general terms, you must do your own research to corroborate the exact behaviour for your device.
I won’t talk of brick your phone, I have confidence you will understand what you propose to do and do not run ahead of your knowledge. It can feel scary, remember there is always the abort option! When we feel scared it is often fear of the unknown. This feeling is an indicator that you need to do more reading/research! If it is too unfamiliar, just stop, make some notes on what you just did and sleep on it. A useful reflection technique is to try to compose an accurate question that you might ask a time stressed geek. As you try to search for the words to define your problem, magically the answer may just come to you.
Before you introduce new software to your phone you must have some knowledge of the hardware.
Other bootable modes
Please now do an online search for “Download mode Recovery mode Samsung”, refine your second search by including your own model.
Please be able to answer for yourself these questions before moving on.
What is Download mode?
What is Recovery mode?
How do I enter each mode
Reliable pages will be found at www.samsung.com in your region.
Learn how to safely get in and out of each of those modes for your Samsung device, with the necessary care.
Review Leaving Bootable modes
I have left you to learn how to get into these modes, here is how we get out. These images are from an unmodified Samsung.
| Download mode | Recovery mode |
|---|---|
 |
 |
| To leave Download mode: press and hold both the | To leave Recovery mode: |
| Volume Down and Power buttons at the same time, for 7 seconds. | 1 Use the Volume buttons to highlight the option Reboot system now |
| 2 Press the Power button to confirm the selection |
The instruction for Soft reset (confirm for your device) is also Volume Down and Power buttons at the same time, for 7 seconds. This is a useful, “get you home” combination which will also work in the “regular” phone to undo an unsatisfactory situation.
Hardware buttons
During the flashing of an /e/ ROM you will control the device with the external physical buttons.
The external buttons are Power, Volume Up, Volume Down, Home/Bixby.
What do you mean Home/Bixby? Samsung have made the writer’s life harder to write an “all devices” article by providing some phones with a button called Bixby and others with a Home button. Please can the reader interpret Home/Bixby as whichever is on your device. Now we see devices with no Home or Bixby button - more research for the reader!
Now we can say:
Access Download mode:
With the phone off, press and hold [Volume Down + Home/Bixby + Power] buttons. (7 - 10 seconds).
When a Download screen first appears watch the screen for follow on instructions. Expect to see a Volume button instruction to either Cancel and leave Download mode or to Enter Download mode.
If you enter Download mode with nothing else going on you see “Downloading…” and “Do not turn off target” - as if it is busy❗
You know this really means “Ready”
Access Recovery mode:
With the phone off, press and hold [Volume Up + Home/Bixby + Power] perhaps over 10 seconds.
Read on screen instructions to Reboot → System, or System Reboot.
Will the reader please add a comment below if this use of language does not work for any Samsung model.
Please do not see this as a conflict with your device specific instructions which should refer accurately to the buttons on your device.
The buttons should be pressed simultaneously. 
The power button executes, so lay your fingers on in the order above so that you are sure to execute with shift buttons already pressed.
Review - did you find out what the other booting modes are?
Short answers, but please do your own research so that in your mind you have sufficent grasp of the concepts.
Android recovery refers to a special bootable partition, which contains a recovery application installed in it.
Download Mode is a special Samsung booting mode, think of it as a communication channel, perhaps. It is locked to Samsung’s tools.
In the Samsung engineer’s description you would use it to download/flash updates, packages and firmware officially using Samsung’s Odin tool, it is also called the Odin mode.
Right now, Odin is only compatible with windows platform but you can use Heimdall if you need alternatives for Linux or MAC OS.
Dear reader, please comment below if you would recommend better links.
What is a stock ROM and how do I get one?
Stock ROM - Stock as is regular factory stock, unmodified - ROM Read Only Memory - the fixed part.
Why would I want one?
You might see it as a fallback if you fear it might all be a big mistake.
It is a requirement sometimes. /e/ is built on top of Android foundations. Installing a Stock ROM puts you at a “known foundation point”. This is an active subject at the moment. Knowledgable comments below would be really welcome, thanks.
Two reliable sources of a Stock ROM are https://www.sammobile.com/ and https://samfrew.com/
What is a Custom recovery and where does it go?
We have seen Android recovery (Samsung’s factory version of it) inside Recovery mode.
A Custom recovery is non Samsung and can be flashed over the Andriod recovery. Flashed, that implies the factory Andriod recovery will be deleted and replaced. What is Android recovery? | Android Central
Samsung engineers did not intend this to happen to their devices, so on screen messages may sound quite negative! For instance “No Operating system found” might mean “No Operating system with a Samsung signature was found”. Please always attend to these sort of messages, think them through or search.
TWRP is a well respected Custom ROM. It is important to have the exact match TWRP for your device. Custom ROMs are also being developed by LineageOS and /e/,
What is Teamwin?
Teamwin or TWRP is software, here is their website https://twrp.me/. I do not intend to discuss software further here, it is an important subject you should have a good grasp of before starting.
Now you are ready to study the software
You will look for the terse instructions by searching your supported device here then look for the link “Install → To install /e/OS on …your phone… click here”.
Study these great tutorials:
It is a significant choice whether you use Linux or Windows. If it is a choice for you, I suggest you make that descision early so that you follow one instruction set only.
Easy Installer
Easy Installer is an /e/ software product which will search for the software for a certain number of supported phones and then with your cooperation install /e/ on your phone. If you have a supported phone, have installed a ROM before and/or understand the workflow it is a really nice idea. Easy Installer is in development and is termed “beta”. If Easy Installer is an option for you grab a large piece of paper and try to understand the workflow before you start.
Easy Installer users please take note of the paragraph below Your first boot into TWRP.
Now you are prepared to commit
Are you? Could you tell a friend how to do it? You can always read more before you start, but if you don’t get stuck with the tell a friend test, go for it!
Do I have to do a factory reset before I start?
Yes. In fact you must also remove all accounts, especially Google, and passwords from the phone before the factory reset. Credit @SuzieQ who has provided the larger part of the author’s knowledge.
Check if you have a Carrier lock or SIM lock - consider if an organisation you pay/paid £$€ to, thinks it has prior claim on your device on account of they ordered 17,500,000 of them branded “your carrier”. In that case you may have to look up how to come to an accommodation with them.
Please remember that this article is intended for reading prior to install. During flashing of software be sure to follow your chosen set of software instructions.
Your first boot into TWRP
Many users fail at this point because they have not thought ahead about what needs to happen!
Samsung devices need be rebooted correctly first time you flash a non-Samsung recovery.
We saw that the device was engineered to support the Samsung ecosystem, and will protect itself from intrusion. Each time the phone reboots it will self check that the phone is “all original”. If you have introduced outside software the device will in the first instance try to overwrite the intrusion back to original.
Where we have just overwritten the Android recovery with the Custom recovery the user neeeds to know:
The key combination Volume down + Power on it’s own is Soft reset and will cause your phone to reboot and the device will over-write TWRP back to original, preventing the install of /e/, without further warning.
The instruction set to make your first boot into TWRP is often abreviated for experienced users, but for a first timer would read:
- Please now Force stop the phone (in the current “Download mode” never mind “Do not turn off target”)
- Use Volume down + Home/Bixby + Power to Force stop.
- Attend carefully, keep holding the buttons - it may take about 7 seconds,
- the instant the screen goes black (black as in off) and before the device starts to restart
- instantly change the finger press to Volume up + Bixby/Home + Power,
- Be prepared for another 7 second hold without relaxing, until Teamwin is seen.
Here, as a video, /e/
Another nice wording to achieve the same is:
- Press all 4 buttons Volume Up + Volume down + Home/Bixby + Power for 7 seconds till the screen dies,
- Release the Volume down the instant the screen goes black
- Keep holding Volume up + Bixby/Home + Power till TeamWin appears
You first sight of TeamWin:
Do not expect to see Android recovery which you started with!
Images; Credit and thanks @piero
Use the eWiki
For further information please be sure to search this resource effectively. Here is the search for
eWiki >> HOWTO >> samsung-galaxy
Increase focus with thousands of permutations like:
/e/Devices >> Samsung >> installations issues
/e/Devices >> Samsung >> samsung-galaxy
/e/Devices >> Samsung >> all
For the quickest learning experience study available Categories and tabs. Notice they don’t work quite the same in Community and eWiki.
OEM Unlock - toggle now missing
Some Samsung devices may have yet another layer of “security”. You started the Software workflow but now the device seems locked again. Solution: first double check you removed all accounts and passwords and they didn’t return when you later used the phone. Go back to OEM Unlock. Is the toggle now missing? Then perhaps Search your problem and/or read about prenormal state
Bon chance.
Post script
What about Fastboot?
The author had made the descision not to mention fastboot as it was thought unhelpful to the target audience. Our software documentation suggests users to avoid fastboot by utilising Odin or Heildall both mentioned above.
To readers familiar with Fastboot on other devices it might come as a shock to find that
fastboot devices
gives an unhelpful reply! To those readers, just avoid fastboot commands. Most adb commands are fine but, for instance, a phone equipped with Download mode may not cope with:
adb reboot bootloader