Sorry but I don't speak Spanish. But I think I have a solution to your problem.
The "modem.img" file delivered with firmware version 106 (baseband MOLY.WR8.W1248.MD.WG.MP.V6.P4) contains (for 3G) the 3 bands: 900 MHz, 1900 MHz and 2000 MHz.
But the "modem.img" file which comes with the firmware version of 108 or 109 (baseband MOLY.WR8.W1248.MD.WG.MP.V6.P10) is only compatible with the frequency: 2000 MHz.
Problem: if your phone has a firmware version of 108 or 109, and if you only change the "modem.img" file by the one from the firmware version 106, it will not reactivate the 900 MHz and 1900 MHz :-(
But I found a solution:
1) make a backup of your SD card (not sure it's important, but I see strange things), and copy on it these 3 files :
2) reboot into
CWM recovery and install a bad but necessary file "image.img" with this script: MT6589_modem_v7_08.05.2013.zip
3) start the phone normally. Attention: at this point, the phone does not pick up the 3G, and maybe even 2G either. This is normal, the v7 does not work with our phone, but installation seems necessary to activate the desired frequencies.
4) reboot back into CWM recovery, and install the "modem.img" file from the firmware 106 with this script: modem_v
106_MOLY.WR8.W1248.MD.WG.MP.V6.P
4.zip
5) start your phone normally. Go to the Engineer Mode *#*#3646633#*#* and make sure the 3 bands: 900 MHz, 1900 MHz and 2000 MHz are activated
If something goes wrong, you can restore the "modem.img" file that came with firmware version 108 or 109 by installing the following script into CWM recovery: modem_v
109_MOLY.WR8.W1248.MD.WG.MP.V6.P
10.zip
Hope this helps you...