To do the following you need to have a rooted phone.
Disclaimer - I am not responsible for anything that you do to your phone.
Originally Posted by downeaststudio
Yeah, you're right, I did. I went to cyanogenmod's website and didn't see any builds specifically for the E739. Do you know where I can find one, and do you know if it includes all the google apps (maps, play store, etc...)?
Before you do anything else get ROM Manager from the Play Store (you may need the full version). Open it, then choose "flash clockworkmod recovery" and select "LG Optimus SOL/TMo LG myTouch". Then choose "Backup Current ROM". This will make a Nandroid backup of your current ROM.
You can also backup your apps using Titanium Backup. Note- if you flash CM9, Google can restore your apps automatically. (CM7.2 is supposed to do it, but it has never worked for me).
Also copy all of your contacts to your SIM card or backup through google. There are apps to save your SMS messages as well if required
Now for the aftermarket ROMs. On Cyanogenmods site alone there are over 30 ROMs for this phone. There is also LEWA OS & MIUI available elsewhere.
For CM 7.2 (Gingerbread based) there are currently 2 release candidates available as well as 2 full versions. I recommend Release Candidate 2 (RC2). There is a known bluetooth bug (they fixed it but forgot to merge before they released it - should be fixed soon), but otherwise is super smooth and pretty damn good. In fact its so good that I UNDERCLOCKED
my CPU 20% as my daily driver without any noticeable lag.
If its ICS that you want, then you need to look at CM9. There are nearly 30 nightly builds (alpha release) currently out. The earliest versions were pretty buggy, I am currently running the nightly from 14 May & I like it a lot. I cannot comment for the newer ones as I have not tried them yet.
Both the CM 7.2 & CM9 are available on Cyanogenmods site CyanogenMod Downloads
On the LHS of the webpage, select your device (E739). This will now give you a list of the Cyanogenmod ROMs available for this device. Select the ROM you want to download.
You will also need Google Apps (maps, etc). I have found a great app on the Play Store called Goo Manager which enables you to download the Google apps packages as well as downloading ROMs from Cyanogenmod all in one easy app. Download the app, open it, then select "download gapps packages". I am using gapps-gb-20120429-signed.zip. You can also select "Browse compatible ROMs", select "/cm/e739/nightly" and pick a ROM
Once you have both the ROM you want & Google Apps downloaded on to your phone you will then need to reboot into Recovery. You can either use something like QuickBoot (or similar) or do it manually. To do this manually first shut down your phone. Now hold both the Power button & Volume Down Button for 3 seconds. At the 3 second mark let go of the Power button & press both the Menu & Back soft keys (still holding Volume down). This may take a few goes before you get the timing right.
When it boots into recovery you will see a text menu. To navigate the menu use volume up/down to move the cursor & use Power button to select item.
Now do the following: "Wipe data/factory reset", then go to "Advanced" and "Wipe Dalvik Cache" as well as "Wipe battery stats".
Now go "Back", then "Install zip from sdcard". Now navigate to where you downloaded the ROM you want to flash and select it.
When the ROM has completed flashing you need to do the same with the Google Apps you downloaded. Once that is done, select "go back", then "reboot system now".
Your new ROM will boot and will put you into the Google Apps part of the installation. Log in to your google account and follow the instructions it gives you.
Once that is completed, restore your apps (only in the case of CM 7.2 with Titanium Backup - restore apps only, NOT data - it will cause problems)
Next: enjoy your new ROM