[Sprint HTC EVO 4G LTE] gpz1100:
Preface: About 3-4 months ago I had issues with the phone not locking to the airave for voice calls, but I could see the mobile light (on the airave) flash for data/3g transmissions. Spent a number of hours with airave tech support trying many different things include phone profile refresh, airave profile refresh, prl updates, factory reset, and some other things. None of these helped the situation. Then, about 2 or 3 weeks later everything worked properly all of a sudden. The 3 beeps returned to my inbound/outbound calls when within the airrave's proximity (indicating call is being routed through it rather than an actual tower).

Observations

After some testing on my end, I discovered several things when this issue was occurring.

From the ##debug#/field trail screen (you need sense for this). I was seeing the following:

http://db.tt/Ql4796Iu

When the phone used to work with the airrave for voice, my sid/nid was 4384/502.

When the issue is present, the phone locks onto sid 22439/120 . By all accounts, this sounded very much like a PRL issue more than anything else. The PRL of the airave had a lower priority than this new SID.

I made a post about this issue on s4gru.com. Shortly after, digiblur (our prl expert) joined the discussion and things made alot more sense. (See this thread for the discussion http://tinyurl.com/ayhk79j )

The solution was obvious, an entry to the prl had to be made that gave the airave greater priority than the 22439 sid, but only acted on one particular NID (502 ---- which appears to be consistent to all airaves, regardless of geographic region). So at this point, I knew what had to be done, but not quite how to do it. Digiblur made a very nice how to guide in the post above - see post #16.

Unfortunately, I never got a chance to actually try this out because sid 22439 was turned off and modifying the prl was no longer needed.... Until now!

About a week ago the issue resurfaced and no more airave for voice calls.

FIX:

*WARNING*: Use at your own risk, all typical and usual disclaimers of flashing anything/everything applies here. If you brick your phone, you can't hold me liable.

1) Pull existing PRL from phone

Unlike the old evo, we can't easily upload a prl to the new evo 4g lte by simply referencing a prl file from the dialer. The process is a bit more convoluted

A) Place phone into diag mode -- ##DIAG# in a sense dialer

B) You may need some new drivers http://db.tt/zc4HIsJK, use proper version for x86/x64. May have to manually force the driver.

C) Download the free version of DFS from http://www.cdmatool.com/

D) After installing and running the program (run as admin), select the proper port next to ports. It will say HTC DIAGNOSTIC INTERFACE COMx. Where x is some number.

E) Provide your 6 digit MSL code next to the box label SPC, then click on SPC to submit it to the phone. In the DFS LOG window, it will say "DEVICE UNLOCKED".

F) Just below where the MSL code was entered, click on PROGRAMMING, and just below that, NAM.

G) At the far right of the NAM window is the tool to manipulate the PRL.

Select READ to read it from the phone, then SAVE to save it to a file.

2) Modifying the PRL

You will need some tool to actually make the edits. I Used QPST's PRL editor.

Follow Digiblur's insturctions below - note, due to new prl's, the line numbers have changed, but the concept is the same.

ref: http://s4gru.com/index.php?/topic/2...-but-not-voice/page__view__findpost__p__60555

Here's what the finished product looks like on PRL 25010, line 460 was added.

http://img268.imageshack.us/img268/9894/prly.png

3) Uploading the modified PRL

A) Referring back to step 1G above, simply load the modified prl into the DFS tool, then click write to submit to the phone.

B) Exit diag mode in the phone by pressing MENU, DISABLE

C) Reboot the phone

NOTE: If you don't have QPST or don't want to go through the hassle of modifying your own PRL, below is the modified one. It's based on PRL 25010; I call it 25011.

25011.PRL http://db.tt/wk9muM1j

So now, when at home, the phone locks to the airave for voice, and either LTE, wifi, or 3G (via airave) for data. Also, it transitions properly too. When the airave is unplugged, phone locks back onto SID 22439. When the airave is again available, phone locks back to it.

Although my particular signal level is acceptable when on the 22439 sid, the airave signal is obviously much stronger. A side benefit is better battery life.