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PRL Goose-chase on the Prevail?

Discussion in 'Android Devices' started by cautery, Dec 22, 2011.

  1. cautery

    cautery Newbie
    Thread Starter

    EDIT: See Post #18 for a short and very basic explanation of how PRL files are constructed/work.

    I think it is, for now... I'm done with PRLs for now...

    1) First, I took 60683.prl and edited it down to ONLY include my GEO 4 area to make it easier to manage/edit. I ALSO set "Preferred Only" to FALSE. Flashed the cut down version and everything worked fine... No better reception or anything... but it worked... Why? Because (as open signal showed), I was connecting to the exact same SID (4120) and same tower...

    2) Next, I set all the Sprint PCS SIDs to the lowest priority in the GEO 4, which placed ALL available NON-Sprint SIDs at a higher priority... The theory being that my phone SHOULD connect to ANY available tower that it comes to ahead of the Sprint Towers... RESULT: It still connected to SID 4120 even though I KNOW there are Alltel towers in reception range.

    So... at this point, I am wondering how to get my phone to connect to ANY other tower.... or IF it can be done.... So...

    3) I further edited the file to REMOVE the Sprint System entries from the file altogether... So, NOW the remaining file is ONLY the NON-SPRINT carriers System/ACQ info that is included in the 60683 (and essentially the same as 11115). Flashed it... Then I READ it back tot he PC to make sure it was the exact file I intended to send.... It was.

    Results? No signal... phone could not or would not connect to ANY tower...

    My analysis: I don't think the Prevail can use any NON-Sprint stuff... at least mine won't. I KNOW there are Alltel and/or Verizon towers all over the place here... My neighbor is a Verizon customer and gets super signal and data.

    My conclusion is supported by my analysis of the 61007.PRL (current BoostMobile PRL)... This file contains ONLY SprintPCS SIDs... and these include SIDs are partially restricted by the removal of certain NIDs with Negative entries on the Sytem List.

    So... I'm done with the PRL chase until we figure out why the Prevail won't connect to non-sprint towers.... Is it in the firmware? (Something we MIGHT be able to change with CDMA Workshop) Or is it in the ROM or other ware loaded on boot? Something we could change (maybe) by editing something...

    Sorry folks... I thought that I was going to be able to do something good for us by chasing down the PRL Tools and learning how the files are structured and work...

    jroderka30 likes this.

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  2. Enzosdad

    Enzosdad Well-Known Member

    GOOGLE 1115.prl - it took me a wile but i found it and before i just changed back to cm7 today was amazing took my 3g speeds to just under 2mbs and that was cause bad ping
  3. trenchkato

    trenchkato Android Enthusiast

    I'm my expirence all the sprint prls work just the same... but at my house I get service now versus the original boost one..

    That is quantifiable difference.. I don't believe the boost 61007 has access to all sprint towers...

    Seeing as boost does not roam, the new towers of vzw are useless in prls...

    60681 60683 11115 11120 will work the same ... accessing all sprint towers

    But thanks for trying to break them down and make them better
  4. cautery

    cautery Newbie
    Thread Starter

    Please don't quote the entire original post when you reply... It makes things hard to read...

    Glad you are happy with your speeds, but I can tell you with 99% certainty that your PRL file change had absolutely nothing to do with it. If you read my original post thoroughly, you'd see that I basically proved that the Prevail (at least MY Prevail) will NOT connect to a NON-Sprint tower...

    I have looked at 01115.prl as well as many others... Until we get the phone changed to make it roaming capable, it makes little difference which PRL you put on it... ALL the files are pretty much the same on the Sprint side of things... It's a matter of whether the phone can access the NON-Sprint content, and then what Priority is set on the SID, etc.
    jroderka30 likes this.
  5. cautery

    cautery Newbie
    Thread Starter

    Well... just in case... I kept 60683.prl on my phone since it doesn't have the list of NEGATIVE exclusions of Sprint NIDs on it like the Boost file did...

    I didn't TRY to break them down... I DID break them down... I analyzed them, then I did a step-by-step analysis/testing to prove that my phone WILL NOT roam outside the Sprint network.

    I can't say with 100% certainty that every Prevail is incapable of roaming, but I pretty convinced that there is something else BESIDES the PRL that is stopping the Prevails from "seeing" outside the SprintPCS world.


    LOL, you edited your post after I started responding... You are correct... while the Boost File may or may not have ALL the Sprint SIDs included, it most definitely restricts some of the NIDs on some of the SIDs to make them "Negative" or prohibited from use...

    We agree... :)
    jroderka30 likes this.
  6. fcortes626

    fcortes626 Android Enthusiast

    have you tried going into the hidden menu and changed home sid, home nid, etc....?
  7. cautery

    cautery Newbie
    Thread Starter

    Nope... Which menu? Access code? I'll give anything a try once... though I don't think this is the magic bullet for our roaming problem. ;)
  8. fcortes626

    fcortes626 Android Enthusiast

    dial menu
    dial ##3282#
    enter ur mls
    *wont work on cm7

    you can change ha spi, ha password, device ip, primary ha ip
    secondary ha ip, home nid, hoome sid, mcc, mnc, accolc. i think some of those have something to do with how the phone connects to the towers. google each of them to see what they do.
  9. cautery

    cautery Newbie
    Thread Starter

    Yep... had that number for the 3G Proxy tweak... Saw the Home SID/NID things... My Home SIS is actually the Kansas City one... who knows...

    Maybe I'll Google a little...
  10. fcortes626

    fcortes626 Android Enthusiast

    i hope some one can make this work. i get cheap reception at my house when my brothers using tmobile get good reception.
  11. johnny424

    johnny424 Android Expert

    hey cautery let me know what you come up with..i was looking in the hidden menu earlier and have questions about other stuff in there
  12. cautery

    cautery Newbie
    Thread Starter

    After a couple of hours of research on the options available in the above mentioned menu system, there doesn't appear to be anything available that will allow a Boost phone to roam...

    Still don't know what convention they use to block roaming on Boost phones, but it almost has to be a firmware/software implementation. IF it's code, then it should be able to be hacked...
  13. fcortes626

    fcortes626 Android Enthusiast

    last time i was on ctmod and i flashed a modified prl and a message appeared saying i was roaming and extra charges might apply. then an r showed above the signal bars. i have got a triangle instead of the 3g icon.
  14. cautery

    cautery Newbie
    Thread Starter

    Then you MIGHT be roaming... BUT, I can mod ANY PRL file to show the roaming icon and give that notification.... It's simply a matter of changing a couple of selections on any given file and a system entry in that file.

    I can make it tell you/me that on a Sprint SID too...
    jroderka30 likes this.
  15. new optimus

    new optimus Android Expert

    Boost has NO roaming on any non sprint tower. that is why it wont connect to alltel towers.
  16. jtsdad

    jtsdad Member

    Doesnt the PRL and roaming only come into play when no available tower from your active provider is available? No matter whet the PRL, your phone still identifies as Boost... so the VZW towers are useless to you as long as your primary provider has coverage and/or no roaming agreement in your area.
  17. cautery

    cautery Newbie
    Thread Starter

    I agree with you... That's why I used PRL Tools and the experiment with 60683.prl to PROVE that I could not FORCE my phone onto a non-Sprint tower.

    But that's not the end of the story, YET.

    I want to find out HOW Boost phones stop roaming... Once we know the "HOW", then we can determine if there is a way around it.
    jroderka30 likes this.
  18. cautery

    cautery Newbie
    Thread Starter

    Yes and no... According to my research thusfar, this is how I understand that PRL files work:

    They are compose of three sections: Properties, System Records, and Acquisition Records.

    Preferred Only: <TRUE or FALSE> If this is set to TRUE, the phone will ONLY try to connect to Systems listed as PREFERRED in System Records.
    Default Roaming Indicator: <ON or OFF or Flashing> Tells the phone what state the roaming indicator should be in by default. IAW, if you set this to ON, the roaming Indicator will be ON UNLESS the phone selects a system that is configured to change it to OFF or FLASHING... thus I could make a file to TRICK the user into thinking they were "roaming".
    Preferred Roaming List ID: <name of PRL file... e.g. 60683 or 11115>
    Roaming List Type: <IS-683A, IS-683B,... IS-683E> Typically for Sprint is IS-683C

    System Records: List systems available within each GEO (Geography Area), and within each GEO area, listed by Priority.
    System Type: <Various... 95(A/B)/1x, IS-856, et al.>
    Geography: <1,2,... for instance, NW Louisiana falls in GEO 4>
    Priority: <1,2,3,...>
    Neg/Pref: <Preferred or Negative> If listed as Preferred, phone MAY selecting. If listed as Negative, phone is PROHIBITED from selecting. Not confirmed whether setting "Preferred Only" in Properties to FALSE will add Negative records here to the MAY list... Not necessary really... you can simply set ALL records to "Preferred".
    Roaming Indicator: <On, Off, Flashing> IF your phone has a working roaming indicator, it will take the state set here... period. IAW, I can TRICK the phone into thinking that it is roaming by setting this to ON, EVEN if it is connecting to a Sprint SID or even its HOME SID.
    ACQ Index: < link to ACQ record to get connection info>
    Assn Incl:
    Assn Tag:
    PN Assn:
    Data Assn:
    SID/MCC: <0-32767 or other depending on SysType e.g. 4120 = SprintPCS Dallas, TX>
    NID/MNC: <0-65535 or other depending on SysType not sure, but perhaps this ID's an individual tower?>

    Acquisition Records: Listed in Priority by Index number, and linked from the System Record by the ACQ Index. Tells the phone stuff about the particular system and how/where to start connecting.
    Index: <0, 1, 2,...>
    Acquisition Type:<Many choices to include CDMA Stanadar, CDMA PCS, HDR, et al.)
    CHAN 1: <dependent upon ACQ Type, but Standard = Block/Band, PCS = channel number = 0-2047, etc.
    CHAN 2: <same mostly>
    CHAN 10: <same for applicable Types>

    The PRL is a PASSIVE file... It simply tells the phone what is ALLOWED. It can't MAKE the phone do anything... You can only ENCOURAGE the phone to select a SID/NID. But you CAN tell the phone it CAN'T connect to a SID/NID.

    Essentially, there are TWO types of "roaming"...

    Roaming WITHIN the network (AKA: Sprint-ONLY): You can use this file to set the Priority of which SID to select. You can also EXCLUDE entire SIDs from the phones select list, OR exclude only certain NID ranges from the list (I believe this is what happens in Boost PRLs, when for instance it INCLUDES SID 4120, but then subsequently adds NEGATIVE records for certain NIDs within the SID 4120 later int he System Records section... same for other SIDs. I THINK this is how Sprint gives Sprint callers tower priority over Boost customers.)

    Roaming OUTSIDE the network (AKA: Sprint, Verizon, et al.): At least two main conditions MUST be met to make this possible:

    1) The PRL must contain System and Acquisition Records for NON-Sprint SIDs. Additionally, the PRL must make these systems available on the "MAY CONNECT" list by setting them as PREFERRED (or maybe, but not confirmed, by over-riding the file with a FALSE on Preferred Only).

    2) The PHONE (or Provider?) MUST enable the mobile device to ALLOW out of network roaming by whatever method they have chosen.... I don't know yet how they do this.

    BUT, if the PHONE is not enabled for out of network roaming, it does NOT matter what the PRL says MAY happen, the phone will NOT roam out of network.

    Additionally, IF the in-network SIDs are set with a higher priority in the PRL and the phone can connect to one of them at whatever criteria set by the provider, then the phone will connect IN-network, regardless of how crappy the in-network service is in comparison to the available roaming service.... IN OTHER WORDS.... you CANNOT use the PRL alone to set roaming preference OUTSIDE the network according to quality of available service.

    OK... I realize this was long, but this is how I understand this, so far.
    Aids10, Lordvincent 90 and jroderka30 like this.
  19. redneckrebel

    redneckrebel Well-Known Member

    Roaming ability is dictated by the IMSI. Network your phone attempts to roam on communicates the IMSI it received to your home network, home network tells the other network either yes allow it or no do not allow it.

    Seems to me it cannot legally be done.
  20. redneckrebel

    redneckrebel Well-Known Member

    I agree. With Boost 60071 I had 2 or 3 bars through most of the house and my kitchen was a dead zone. With the Sprint 60681 prl I now have full signal strength in the kitchen and just shy of full strength throughout the rest of the house.
  21. cautery

    cautery Newbie
    Thread Starter

    CONFIRMED: REGARDLESS of the "Properties:preferred Only" setting: TRUE or FALSE... IF a "System Record:Neg/Pref" is set to "Negative", that record/SID will not be available to the mobile device.

    If you set "Properties:preferred Only" to TRUE, then ANY SID that has a "System Record:Neg/Pref" set to "Negative" will be EXCLUDED from the "May Connect" list.

    Condition: If you set "Properties:preferred Only" to FALSE, then ANY SID that has a "System Record:Neg/Pref" set to "Negative" will be EXCLUDED from the "May Connect" list.

    Details: "SID 4120 - SprintPCS" is the SID to which my phone normally connects. I modified 60683.prl to set the SID 4120 System Record to Negative. Under both test conditions, my phone did NOT connect to 4120 and sat there with greyed out signal bars during acquisition, and finally "Red X'ed" to "No Service".

    I don't know what the "Properties:preferred Only" Header setting is intended to do. Perhaps it is just a "notice" to the developer with no actual function in the file other than information. For our purposes, it doesn't really matter.

    What matters is that the "System Record:Neg/Pref" value determines whether a particular SID/NID combination is available to the phone or not.

    AND it appears to be a "subtractive" setup... meaning:

    If you set SID 4120 with a NID value of 65535 to PREFERRED in the main record, and then add a subsequent NEGATIVE record(s) for SID 4120 with a specific NID of say 501-513 (13 records), then it EXCLUDES that/those NID(s) from the MAY/AVAILABLE list. (This specific setup appears in the Boost 61007.prl file) Thus, it appears that a NID setting of 65535 means ANY NID available, subject to subsequent NEGATIVE records for that SID.) Clear as mud, right? ;)
    jroderka30 likes this.
  22. im a genius

    im a genius Well-Known Member

    prl 11115 works very good
  23. cautery

    cautery Newbie
    Thread Starter

    I suspect that you are correct with respect to the legality... This is mostly an academic exercise at this point. I MAY not always be on Boost, so I want to learn what I can.

    Do you have a source for your assertion that roaming is dictated by the IMEI and controlled by some setting on the "home network", rather than some setting/code on the phone? Just curious...
    jroderka30 likes this.
  24. cautery

    cautery Newbie
    Thread Starter

    Unless Boost has set some out-of-network exception for your local area, 11115.prl can ONLY be better to the extent that is does not have any System Record exclusions for specific NIDs on Specific SPRINT SIDs... Otherwise, you are still ONLY connecting to SPRINT SIDs.

    Sad, but true...
    jroderka30 likes this.
  25. Roguefoxx

    Roguefoxx Android Enthusiast

    I don't have any coverage issues with the default PRL on my phone, which I'm assuming is a Boost PRL, although my 3g speeds aren't very good at all. Would it make any difference if I were to try to switch to a Sprint PRL?

Samsung Galaxy Prevail Forum

The Samsung Galaxy Prevail release date was April 2011. Features and Specs include a 3.2" inch screen, 2MP camera, GB RAM, MSM7627-3 processor, and 1500mAh battery.

April 2011
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