For many Android users, the process of flashing a new ROM – a phone’s firmware or operating system – seems shrouded in mystery. But it’s actually a doddle. Jason d’Allison shows you how...
In this two-part guide (Windows-only, sadly), I’m going to explain how to flash an Android phone with a new ROM. This week, it’s the turn of stock ROMs, ones provided by a phone’s manufacturer or network provider. Next week, I’ll venture on to custom ROMs, ones developed by enthusiasts to give improved functionality.
For both parts, I’m using a Samsung Galaxy Note (GT-N7000). Firstly, I’ve got one to hand, and secondly, there’s a solid chance a Samsung is what you’re holding, as the South Korean colossus sells more Android phones than all the other players combined. The flashing process is largely the same across the whole model range. Unfortunately, it’s often somewhat different with other Android brands, but this guide can still serve as a useful foundation.
But why flash a stock ROM in the first place? Why not just install the regular OTA updates (over-the-air) or use Samsung’s Kies software? Well, you should always do that if possible, but if your phone is rooted or tweaked or running a custom ROM (perhaps it’s second-hand and came that way), both of those routes will likely be blocked. Manual flashing could be your only get-out – crucial if you need to make the phone ‘official’ again for a warranty claim.
Read Me First!
Before you start, ensure you’ve backed up everything of value. Ordinarily, you won’t lose the content of a micro-SD card, nor any files stored internally in the phone’s default media locations, but it’s wise to proceed as though you could lose the lot.
Apps you’ve installed via the Play store, and often their settings, will normally have been backed up automatically to Google’s servers. You’ll be able to restore these as soon as you log into your Google account in the new ROM. The same applies to Gmail messages and call contacts. Take a look at goo.gl/LU5IrM if you’re unsure how all this works.
To save text messages, a good bet is SMS Backup & Restore, a free app in the Play store. And to save media files, simply hook your phone up to a PC via USB and copy them across. You could also use Samsung’s Kies (goo.gl/Zl0gqv) – or the company’s new Smart Switch (goo.gl/2UwU1w) – but as mentioned before, this will typically only play ball if your Android installation is totally Samsung-stock.
Now, there’s an app that’ll do all the above at one fell swoop: Titanium Backup. This is also in the Play store. One snag is that some features – including text-message backup, sadly – are only available in the paid version, currently costing £4.11. Another snag is that your phone needs to be rooted, a concept I’ll explain next week.
Step 1
First, choose your ROM. The best place for Samsung ROMs is probably www.sammobile.com/firmwares (alternatively, try samsungupdates.com/latest-firmware). Use the search bar to find your phone model – the *exact* model – then hit the magnifying glass. A long list of ROMs will appear. Obviously, you’re only interested in the ones offering the latest Android version your model supports.
Step 2
Every Samsung ROM has a CSC (carrier sales code) that defines its intended region and network. Common UK CSCs are BTU (unlocked), CPW (unlocked), H3G (3), O2U (O2), ORA (Orange/EE), OXA (unlocked), TMU (T-Mobile/EE), TSC (Tesco), VIR (Virgin), VOD (Vodafone), and XEU (unlocked). Use the ‘Select country’ menu to home in on the UK ROMs, and for help on which CSC to go for, see Network Notwork.
Step 3
To get hold of your ROM, you’ll need to register. The site will try to persuade you to get out your wallet, but keep it in your pocket. Take the free option. The catch is that the download speed will be capped. Badly. The Android 4.1.2 CPW ROM for my Note weighs 788MB, so in theory it should have romped down my 76Mbps fibre pipe in under 90 seconds. It took an hour. Go and get your hair cut or something.
Step 4
Next, equip your PC with Samsung’s USB driver. This comes with Kies, but if that’s not set up (perhaps it doesn’t like your phone), install this stand-alone job: goo.gl/GTqyGn. Also, you need to install Odin, the actual flash tool. Grab the latest version, which is currently v3.10.6: odindownloader.com. The ROM, driver and Odin downloads will be zip files, so be sure to unzip them. You’re then ready to rumble!
Step 5
Make sure your phone has enough juice or plug it into the charger. The flash process should take about five minutes. First, get the phone into download mode: switch it off, then switch it back on by simultaneously pressing the volume-down, home and power buttons. It can be tricky to get this right, but when you do, a warning screen will appear. Pay it no heed; press the volume-up button to continue.
Step 6
Next, connect the phone to your PC via USB, then launch Odin. The first ID:COM box should turn blue and display a number. Click the AP button (labelled PDA on older versions) and open your ROM file. Don’t panic if Odin freezes up and shows ‘Not Responding’ – just wait. Leave the settings alone – only Auto Reboot and F. Reset Time should be ticked (these are hidden under the Options tab on recent versions).
Step 7
Now click Start. This is when the magic happens! You’ll see progress bars – blue on the phone and green in Odin. Wait while Odin works through the following stages (they may differ slightly in your case): CACHE, FACTORYFS, HIDDEN, MODEM, KERNEL, RESET! and PASS! The phone will then reboot, and you can unplug the USB cable now and close down Odin. Andy the Android should have a blue spinning thing in his tummy.
Step 8
After a while, the phone will reboot again. If it gets stuck at this stage, start worrying! No – I’m joking! A freeze-up here is more or less normal. The answer is to put the phone in recovery mode: switch it off, then switch it back on by simultaneously pressing the volume-up, home and power buttons – volume-up this time, not volume-down. You’ll be greeted with a text menu, possibly with a red error message near the bottom.
Step 9
Use the volume buttons to move up and down the menu options and use the power button to make a selection. First, select ‘wipe data/factory reset’. On the next screen, select ‘Yes – delete all user data’. It all sounds rather ominous, I know. Before long, though, your phone will reboot to the recovery menu again. This time, select ‘reboot system now’. Once that’s done, so are you. Success! Your phone will be factory fresh.
Network Notwork
If your phone is locked to, say, Vodafone, you’ll normally be fine using a ROM with, say, an O2 CSC. One reason for doing this is if Samsung has made an update available but your own network hasn’t yet released it. If you run into boot difficulties, panic not. Just try again with a different ROM.
The downside of fudging the CSC is that you’ll end up with the wrong network-specific apps and branding. True, such things can be removed by rooting, but that’s a subject for part two of this guide. Most of the time you’ll want a ROM with an unlocked CSC, with no network-specific apps and branding at all.
However, flashing an unlocked ROM to a locked phone will *not* remove the lock. Sorry! Likewise, if you flash a ROM with an O2 CSC to a phone locked to Vodafone – to use the above example again – you won’t magically be able to use an O2 SIM. A phone’s network eligibility is linked to its IMEI and held on an external database.
Security Alert
Beware! Most Samsung phones running stock Android 4.4.x or later – or 4.3.x in some cases – have the Knox feature. This provides two separate Android environments: standard and secure. In the secure environment, only certain apps are available, and there’s no Play store. Also, nothing created in one environment is visible in the other. The idea is that the same phone can be used for both home and work.
Knox relies on a security flag, which can be either 0x0, for untripped, or 0x1, for tripped. Do pretty much anything unofficial and the flag will trip. The process covered by this guide will trip it, as will rooting (usually). Under Knox, the only ‘safe’ ways to modify or change a ROM are to install an OTA update or use Kies.
On a phone with a 0x1 flag, Knox becomes disabled. At least in the US too, the phone’s warranty becomes void. In most instances, Knox can never be used again, as normally the flag can’t be reset. Indeed, there’s often an e-fuse in the SoC – the system-on-a-chip – that gets physically ‘blown’.
If you’ve no interest in Knox and if your phone’s warranty has already expired, the security flag needn’t be a concern. Even when tripped, it won’t limit what you can and can’t do except as noted above. For more information, head to goo.gl/JoAdF5. And again – beware!