First of all, this is not meant for those who already know the basics of flashing. I will not go deep into details of why and how but instead concentrate on making this as easy to follow as possible for all newbies.
Now, before you begin your exciting and often nerve wrecking first custom ROM flashing, take a deep breath. There you go. Feeling better? No? Well, didn’t think you would. But that’s fine, that’s what this guide is here to hopefully easy your anxiety and allow you to have higher confidence when you take that leap into the world of custom ROMs.
I will address a few usual questions I get before I proceed on the how-to.
Q1. Why should I flash in a custom ROM?
A1. Custom ROMs usually offer benefits like better battery life, less cluttering of not-so-useful OEM materials (like Samsung Apps, HTC Likes, etc), additional functionality and better support for upgrades.
Q2. Doesn’t it void warranty?
A2. Yes it does. In most cases though, you should be able to flash back to the stock ROM before sending it to customer service should any hardware issues occur. There are contrasting stories on this and I have not had to send mine back to customer service so I can’t say for myself but there are those who claim that customer service is still able to detect that it has been custom-ROM-ed and those who says otherwise.
Q3. What is the difference between using a custom ROM and putting on a custom launcher like Go Launcher Ex?
A3. Any custom launchers like Go Launcher Ex are just manipulating the surface of the GUI. Their changes do not and, in some ways, cannot go deep. Think of it as a custom launcher is just putting on makeup while a custom ROM is altering the way you look completely with bone/tissue manipulation.
Q4. Is it safe?
A4. As with all things custom, there are risks. Understanding the risks will reduce the likelihood of hitting an issue but it is almost impossible to say that there are no risks involved. Taking your time to read the instructions, checking and double checking your facts will help. When you’ve done a few custom ROM flashing, the risks of hitting an issue will be very low. Having a backup plan also helps in case the unwanted really does happen.
If you have any questions, do feel free to ask. The community of custom ROM developers and users are usually friendly and willing to point you in the right direction. The developers only ask that you refrain from asking some stupid questions like the ones below:
1. When will XXX<Insert custom ROM version> be released?
-> Rule of thumb, do not ask developers for date/time of release. They are working for free for you. Be polite and wait. Its the least you can do. Feel free to donate some cash to them, but do not think that donating some cash to them makes you their king and gives you the right to demand things.
2. Is XXX<Insert feature> supported?
-> Read the feature list/changelog. Search the forum/thread first before you ask. It is fine if it hasn’t been answered before but don’t ask a question that has already been answered hundreds of times. In general, read and search first.
3. Is XXX<Insert bug> fixed?
-> As above, read the changelog and search the forum/thread first.
You may email me any questions you have and I will try my best to answer them. However, do not spam my email please: eric10234 at gmail.com
Now, onto flashing custom ROMs. Since I have a Galaxy SII, I will only cover for Samsung phones. If I do get enough request, I may try to do something for HTC users, but for now, it will be purely Samsung.
There are two distinctive types of flashing:
1. Through Odin
2. Through CWM
1. Through Odin
This method utilizes a PC connection and your phone needs to be in “Download” mode. This is reportedly the same method that Samsung service center uses to flash the stock ROMs. This method can be dangerous if you do not follow the instructions exactly as the wrong settings or the wrong files in the wrong places can and will screw up your phone, resulting in a bricked device. A bricked device is a device that is no longer able to operate (read: turn on) and hence only has the usefulness of, well, a brick. A pretty, shiny looking brick, but still a brick.
i. Download the appropriate .tar or .tar.md5 or .md5 file(s) for the custom/stock ROM you want to install.
ii. Downlaod Odin (versions may be different depending on which Samsung phone you are using, when in doubt, search for the one people are using with your phone. If you can’t find the suitable one or if you’re unsure, drop me a line with your phone model and I’ll see what I can do.
iii. Open Odin and leave everything as default. The only things you want to click are usually the PDA, Phone/Modem and/or CSC. Typically, just the PDA will suffice. Select the .tar, .tar.md5 or .md5 that you’ve downloaded in the correct place. The developers usually will have something with PDA, Phone/Modem or CSC in the file name to make it easy to identify. If they only have one file, its usually the PDA.
iv. Boot your phone into “Download” mode.
v. Connect your phone to PC using the USB cable and wait for the ID:COM turn yellow. This indicates that the connection is found.
vi. Click Start and be patient. The phone will reboot itself when it is done flashing.
2. Through CWM (Clock Work Mod)
This method uses zip files already stored on the phone’s internal memory and is normally not very dangerous except if the file you are flashing is corrupted. This is also the more common methods to flash in a new custom ROM.
i. Download the zip file of the custom ROM that you want and place it into your phone’s internal memory.
ii. Boot into “CWM Recovery” mode.
iii. Select “wipe data/factory reset”.
iv. Select “wipe cache partition”.
v. Select “advanced” -> “Wipe Dalvik Cache”.
vi. Select “+++++Go Back+++++” -> “install zip from sdcard” -> “choose zip from sdcard” -> select the zip file that you’ve downloaded.
vii. Once it’s done, select “reboot system now”.
“Recovery”/”CWM Recovery” mode
-> Hold Volume Up + Home + Power buttons when the phone is powered off to launch into “Recovery”/”CWM Recovery” mode.
-> Navigate using the Volume buttons and select using the Home button. Some newer versions of CWM Recovery mode that is meant for ICS devices may make use of the Power button to select.
-> To exit, select “reboot system now”.
-> Hold Volume Down + Home + Power buttons when the phone is powered off to launch into “Download” mode.
-> Download mode is only for flashing via Odin. You will rarely need to access this if you’re using CWM to flash your ROMs.
-> To exit, just hold down the Power button until it turns off. Then power on as usual.