[T-Mobile LG G2x] Core Memory:
The following was done while my phone is using the WIND SIM card which is my carrier and is restricted to AWS (WCDMA 1700) and Network Mode is set to WCDMA only.

I used your instructions to enable the UMTS 850 and 1900 MHz bands. One clarification is necessary. The HexaDecimal number 0x6e80380 = Decimal number 115868544 = Binary number 0b110111010000000001110000000.

The binary number is read from right to left with the first binary bit on the extreme right designated as bit 0 of the 27 bit sequence. The binary number is the key to the hexadecimal number used to program the RF Band Configuration in QXDM. For example, according to Jwells777, bit 23 is set to binary 1 to enable WCDMA Band II (band 2) and bit 26 is set to binary 1 to enable WCDMA band V (band 5). Refer to Jwells777 post in this thread which states the binary bits used to set the phone to use the phone's bands. Here's a binary-decimal-hexadecimal converter: http://www.mathsisfun.com/binary-decimal-hexadecimal-converter.html

The HexaDecimal number 0x000000006E80380 can be entered directly for setting "RF Band Configuration" at line 1877 in the NV browser. The HexaDecimal number is converted into the decimal number 115868544 which will appear when another read is performed. In Engineering Mode, the SW Enabled Band reading of my phone changed from 0x0000000102400000 to 0x0000000106C0000. When I changed the phone's setting to Automatic Band Selection, the SW EnableBand reading changed to 0x0000000106e80180. Changing the settings for Band Selection and/or Network Mode will change the SW EnableBand reading on page 5 of Engineering Mode.

In Band Selection, I enabled WCDMA 1900 which caused my connection to WIND's AWS 1700 to drop. I Looked at page 5 (RF Calibration) of Engineering Mode to see which bands were activated and found:

WCDMA1 : 22.37, 22.45, 0.00

WCDMA2 : 0.00, 0.00, 0.00

WCDMA4 : 23.47, 23.19, 0.00

WCDMA5 : 0.00, 0.00, 0.00

WCDMA8 : 0.00, 0.00, 0.00

GSM850 : 32.70, 32.63, 0.00

GSM900 : 32.76, 32.71, 0.00

DCS1800 : 29.40, 29.50, 0.00

PCS1900 : 30.10, 29.90, 0.00

LOSS:

-1.06, -1.18, -1.24

-1.54, -1.64, -1.74

-1.80, -1.79, -2.01

-2.11, -2.21

The same readings occur with Band Selection set to Automatic or manually to any other band except AWS which is the UMTS band the phone was set up to use at the factory.

This indicates that WCDMA2, 5, and 8 are not RF calibrated but DCS 1800 and PCS 1900 are RF calibrated.

I also found that

When I do a network search, it finds WIND and Public Mobile which operate on UMTS 1700 (AWS) and Bell and Telus which operate on UMTS 850 and 1900 but not Rogers which also operates on UMTS 850 and 1900. (Rogers does appear if I search for GSM networks too.)

"In Canada, UMTS coverage is being provided on the 850 MHz and 1900 MHz bands on the Rogers and Bell-Telus networks. Bell and Telus share the network. Recently, new providers Wind Mobile, Mobilicity and Videotron have begun operations in the 1700 MHz band."http://en.wikipedia.org/wiki/Universal_Mobile_Telecommunications_System

That indicates it is able to receive signals on UMTS 850 (Band 5) and 1900 (Band 2) which should enable the phone to see TELUS, Bell and Rogers.

http://en.wikipedia.org/wiki/UMTS_frequency_bands

When I select connection to Bell or TELUS, the phone tries to register but fails with the message: "Unable to connect to this network at this time. Please try again later." That message is generated by the phone's firmware/software, not the network.

I haven't yet tested the phone with a SIM Card for Rogers or Bell or TELUS. A friend has a Rogers SIM card with a data plan but I don't think it will be of any use to test the phone's supposed additionally enabled bands.

Conclusions:

Cognitive overload.

I am finding this quite confusing because of the variable terminology used such as UMTS, WCDMA, PCS, DCS, and the various bands and transmit and receive frequencies used for each protocol. If someone could make more sense out of the information I've provided, that would be very helpful.

Questions:

Engineering Mode Page 5 (RF Calibration) indicate that WCDMA Bands 2,5, and 8 are not RF calibrated but DCS 1800 and PCS 1900 are. Does this mean that the phone will not transmit on the WCDMA Bands 2,5 and 8 because the RF calibration for transmitting is not available?

If anyone can add something useful to this thread, that would be greatly appreciated.