Im am not sure why no one else has not done this yet but I felt it was about time we had our own dedicated radio thread. Some of you may wonder what a radio is and others may have misconceptions as to what radios do. So let me try to make this clear and simple for all of you. So in a nutshell a radio driver is what allows your phone to communicate with the cell tower, similar to how a printer driver lets the computer and printer communicate with each other. Keep in mind it's a lot more in depth than that but you should now have a basic idea as to what they do.
I would also like to take the time to clear up some common misconceptions as to what radios do and don't do. Now most of this is fact, it is not just an opinion so if you have an open mind you can learn something. However, if you try to argue with me you better come up with a valid argument explaining why you believe what you believe. Different radio firmwares will more than likely NOT give you a stronger signal. Before a phone is released it is excessively tested before being released to the public. During this time the carrier/s test how much power the radio antenna can safely transmit. The way they measure this is through the SAR (Specific absorption rate (SAR) is a measure of the rate at which energy is absorbed by the body when exposed to a radio frequency (RF) electromagnetic field) value and then it is submitted to the FCC. Verizon's fillings are listed as below, in order for these to be raised above this the phone would have to be resubmitted to the FCC.
SAR: Head: .63 W/kg ; Body .88 W/kg , Product Specific Use: 1.01 W/kg, Simultaneous Transmission: 1.39 W/kg - (max allowed by the FCC is 1.6 W/kg)
What they will do is control when the phone will switch from 4g to 3g to 2g. This will cause some of you to be able to hold on to a 4g or 3g signal in some place that you didn't used to have it.
Radio drivers can also change the way the phone displays a certain signal strength by changing the way the signal to noise ratio is sent to the android telephony file in the platform_frameworks_base ... EXAMPLE -89dBm 43asu used to give you 2 bars of service. If they want to service providers can manipulate this to where the phone now shows 4 bars of service. Apple has done this in the past and Verizon admittedly did this with the 4.0.4 OTA.
Default values of SNR will display like this...
The LTE signal strength level is the smaller one
between lte rsrp level and lte snr level if both
rsrp and snr are valid.
The lte snr mapping are
Four bars: SNR >= 45
Three bars: 10 <= SNR < 45
Two bars: -30 <= SNR < 10
One bars: SNR < -30
No bars: No Service
One final misconception I would like to clear up is that a radio update, assuming everything I stated prior remains true, should not make your phone's download speed faster. There are numerous variables that will cause the speed of your network to fluctuate. If you flash a radio and notice an increase in speed, whether it be small or large, you are only experiencing a placebo effect. The only file in android associated with download speeds is the build.prop file. With the exception of user traffic what I quoted below will be the biggest cause in difference of network speeds.
Reference signal received power (RSRP), is defined as the linear average over the power contributions in Watts of the resource elements that carry cell-specific reference signals within the considered measurement frequency bandwidth. Used to measure the signal of your LTE (GSM/4g) connection. In short, it's what's used to determine the best cell tower your LTE device can connect to at the given time. Anything below say -80db is considered pretty good and you're pretty close to a tower. -80db to -90db is average what you should expect most of the time. -90db or above and you're probably in an "extended network" area for LTE and getting close to a likely handoff. -105db and above you would be likely to see a handoff to 3G if your signal does not get better.
Throughput for your connection measured with LTE is estimated to decline between 30-50% if your signal goes from -75db to -90db for RSRP. Above -95db and your throughput dramatically drops. At around -108db and worse, your throughput for download drops to nearly 3G rates or worse. Note that this doesn't exactly represent how strong your signal is, just the potential of how efficiently it will send that data.
"But why can I have a super awesome RSRP signal and still my download/upload speeds are not that good (or why is it still sometimes good when RSRP is low)?"
Because it's only measuring the efficiency between you and the tower, not the rest of the network or the end source (the website). There are many network hops along the way to the destination and some may also handle connections inefficiently. The more hops, the slower the connection generally is.
However, it does also represent the greater likelihood that your connection will drop more packets of data that need to be retransmitted and thus not only slowing your connection but also causing it to have to work harder and draining more battery when it's actively downloading/uploading. That's why having it hand off is for the best than fighting it to stay on LTE. This is most likely why people always complained about the Thunderbolt having such poor battery life as no one ever saw what their RSRP was on it, only their RSSI like all other Gingerbread devices.
All of these files are flashable through a custom recovery. If you would rather use fastboot just unzip the file a move the radios to your fastboot folder,
2. Its is VERY important that you check and match the md5 sum before flashing.
3. Wipe cache and dalvik cache (optional)
AS ALWAYS FLASH AT YOUR OWN RISK. IF SOMETHING GOES WRONG ONLY YOU ARE TO BLAME
1. Nandoids do not back up your radio and no you don't need to back up a radio.
2. There is no need to wipe yet I suggest wiping your cache and dalvik cache anytime you flash anything.
3. Yes you can go back radio versions if you don't like the one you are on. Just download and flash the desired radio.
LTE-EK02 / CDMA-EK01
MD5 Sum: 3302017119dd24eaf99b2a6540ea3697
LTE-EK02 / CDMA-EK05
MD5 Sum: a12743e6d3b80734831f69502bdae29b
LTE-EK04 / CDMA-EK06
MD5 Sum: c07f43102346b7e88ac30fe981dbbf2b
LTE-FA02 / CDMA-FA02
MD5 Sum: bd63961006aa65e88100017bab2c7fbb
LTE-FC05 / CDMA-FC04
MD5 Sum: 498a0596e23a155e80676dbbd6ac426f
LTE-FG02 / CDMA-FF02
MD5 Sum: 576354b2d830daa8961847042ef90918
4.2.2 (JDQ39) Thanks Mwalt his thread here
LTE FK01/CDMA FK02 Radios
MD5 Sum: 9d9841c7ee3d1e46ba30c013adf50d2a