Upgrade Firmware

Galaxy s plus i9001 is minute upgrade from the first gen flagship device of samsung.It comes with a snapdragon chipset which is clocked at 1.4ghz with 512mb of ram.All other specs of the device remain unchanged.

samsung never updated its software to latest android after gingerbread.But this device is well know in android development ecosystem, as a result  there were many custom roms that soon or later paved way for latest android updates.If you are still on stock or other kitkat its time for you to upgrade once again.

If you still own samsung galaxy s plus i9001 either as a primary phone or secondary device,you can now update it to latest version of android lollipop by flashing cyanogenmod 12.1 custom rom.One of biggest challenging task that developer has to face while compiling any custom rom for this legacy device is that he has to make it bug free so that it encourages other developers to use his sources or other members to flash custom roms on galaxy s plus.

If you are flashing roms from a long time then you must be aware of that we take no responsibility for any type of damages that happen to your s plus after flashing this  cm 12.1 rom.If you brick your device even light from mars or Pluto will not save it.So proceed at your own risk.
Before going further:

• Check you samsung galaxy s plus model number by going into about device and confirm that you are using I9001 only as flashing o other carrier variants might brick it.
• Make sure that  kies (drivers) is already installed on your computer.If you don't have then do install them.
• You must have updated it to official software that is already available if you are starting from scratch.
• Root: You need to have root access on galaxy s plus i9001 to install cyanogenmod custom rom .
• Backup:Backup all your data which includes contacts,apps,photos videos etc everything to computer or any cloud networks as Flashing Cm 12.1 custom rom on your galaxy s plus I9001 might erase all the data on your device.
• Backup Efs partitions: This is for those who already have twrp installed.Backup all your efs partition of your samsung galaxy s plus on existing rom.Just in case if you loose signal or imei  you can just restore it back.
• Battery: Charge your I9001 so that you wont encounter any battery related problems while updating it.
• You must have a unlocked bootloader on your galaxy s plus to flash this rom.
• Downloads:Lollipop based cyanogenmod rom for s plus(androidfilehost) on your computer or device itself.If you want gapps download them too.(gapps androidfilehost)
• Recovery: You need a custom recovery like twrp with new partition layout  already installed on your I9001.

Update galaxy s plus i9001 to android lollipop 5.1.1:

Update samsung galaxy s plus I9001 to lollipop using cyanogenmod 12.1

About cyanognemod 12.1:
Cyanogenmod 12.1 is one of the best custom roms available in android development ecosystem.They support lot of devices.This rom is based on android open source project with lot of added features.
This is not an offcial cm 12.1 rom from cyanogenmod, it has been compiled by a xda member "Christopher83", a big thanks to him for bringing this rom for galaxy s plus i9001.

cyanogenmod 12.1 rom for s plus i9001

Rom being compiled from kitkat and some older sources it is quite common to have bugs.But most of the features that  are essential for daily needs are already working great without any issues.There is small bug in camera which doesnot let you to record 720P videos at all, so you need to stick to 480p.
General Features of cm 12.1:

• Theme engine: Theme engine is from the cyanogenmod custom rom which basically changes the look user interface from lock screen  to ring tones all the way up to boot animations.The speciality of the theme engine is the ability to choose individual elements of every theme you have installed.So you like the ring tons and wallpapers of one theme and icons of other theme then you can have them at a time.Just open the theme chooser and you will understand how to do it.
  
• Performance control:A default cpu manager app to control frequencies and governors.You can adjust cpu frequencies and also set them on boot too.
• Trebuchet: This is the default launcher that ships with cyanogenmod rom.But if you flash gapps then you might loose this.It doesn't have too many features like nova or other launchers but its simple and fast.
• Software Updates: Cyanogenmod rom is usually available in three types one is nightlies which gets updated with new features every night and are quite stable for daily usage.second one is the snapchat which is monthly build version which will be stable version and other one is the release candidate.Some times nightlies are considered must stable than the snapshots. 
• Status bar Tweaks:Status bar has lot of tweaks which include a brightness slider.Slide in status bar to adjust brightness of the screen.Double tap on status bar to sleep device and also network speed indicator for on going traffic info.
  
• If you root apps dont work then that is no response form super user it means it has been disabled and you can enable it in developer options easily.