Many thanks to @iulykenoby who discovered this method.
To start, download a KDZ firmware for your LG E460 (and other phones) from here: http://lg-phone-firmware.com/index.php
Be sure to match the phone with the right kdz!!!
1. Download LG_KDZ_FW-Update_OfflineFix.ZIP (attached)
2. Download USB Driver http://algmcdn.lgmobile.com/dn/downl...=UW00120120425
If you can't boot anymore, enter into download/emergency mode and skip to step 5.
3. Put your phone in debugging mode (menu-Settings-Developer options-USB debugging).
4. Change your usb connection type to LG Software (menu-Settings-USB connection type)
5. Connect your phone to the PC and install USB Driver. After the installation disconnect and connect your phone again (to make sure it is detected).
6. Extract LG_KDZ_FW-Update_OfflineFix.ZIP
7. Run B2CAppSetup.exe and let it install and update itself. You may be prompted to update your drivers.
8. If you've done everything correctly, you should see this:
9. Close the official LG Mobile Support Tool.
10. Open Notepad in Administrator mode. (Go to windows menu, type notepad and right-click and run in Administrator mode)
11. Open the hosts file (c:\windows\system32\drivers\etc)
12. Add 127.0.0.1 csmg.lgmobile.com at the end of the host file.
13. Save the file. If the "Save as" dialog opens, it means you're not running notepad in administrator mode and you can't modify the hosts file.
14. Go to windows menu, type cmd and right-click and run in Administrator mode.
15. Drag Automatic Offline Procedure.vbs over command prompt and hit enter.
16. Click OK
17. Click on windows enable icon in system tray to turn ON then click the dialog box OK.
18. Click Ok.
19. Make sure Type is set to 3GQCT and phone mode to DIAG. Select your KDZ file and click Normal web upgrade test.
20. Click on Upgrade Start.
21. Click on Clear phone Software update Registry and then click OK.
22. Software Update Procedure will start immediately. It will take some time to finish.
After the flashing procedure, don't forget to delete that line you added in hosts or else you won't be able to officialy update (online) your phone and you won't be able to download anything from lg. Also, a factory reset may be needed after flashing to avoid conflicts with the old app data.