{Trick} Get Around "RAT SELECTION RESTRICTED" on i897 modems!

FAQ, at OP's request


1.

Does this mean UL/DL speeds can be improved on those listed modems?

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and in response

Johnsondr80 said:

Not there yet. But they say 850 is faster due to less users clogging the line.

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This does not effect data speeds because this has nothing to do with HSDPA/HSUPA/HSPA+. That is dependent on something written within the modem that XDA is yet to learn about. (no one seems to wanna touch the modems, in part because they are heavy with proprietary code for things like the bluetooth chip and the GPS chip. proprietary = closed source and a PITA to mod) Tho using GSM = 2G and WCDMA = 3G, so be careful about which 850 or 1900 band you are choosing.

2.

And the same bugs with using a I9000 kernal aply, no buetooth, is that corect?

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This does not allow for mismatch with kernels, as that is HW communication dependent. Your kernel talking in a 1234 pattern and your modem talking in a 4321 has NOTHING to do with RAT or the band/frequency that your phone it trying to speak to the antenna with.

3.

I have tried this a couple times and it doesn't seem to work for me. RAT is still restricted at the main menu.

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This does not remove RAT, it gives us a means to work around it. At this point we still don't even know what triggers RAT as some I897 users have shown to not have such restrictions. Until we have figured that out we can't kill RAT, tho we do know it is something within the I897 aka AT&T modems.

4.

I notice if I reboot my phone it sets back to 1900 again. I made sure to follow the steps correctly three times. Is this how it works?

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and in response

Johnsondr80 said:

Most times it will stick past reboot.
Unless you visit recovery for some reason and then reboot from there.
Try a airplane toggle
I find that if I get back on 1900 for some reason. Airplane mode for a second and it goes back to 850.

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Settings may get dropped on reboot, sry but for now this is only a change held in the RAM.

Other things to note:​

Phone stays on and running the whole time. The most time consuming part of this is waiting for the phone to realize the removal/insertion of the sim card.

-SGS Tools / nitrality- apps have the "secret/service codes" to speeds up and or ease the process.

No love for WCDMA 900... even on fully auto that lone band is unused.

Folks, follow the instructions exact, and take your time. I tried toying around and skipping = not successful.
Lastly you can't seem to force it to run an unsupported band (like I did with the WCDMA 900), it will eventually seek its way into service again. Keep in mind that having RAT means we have limited control over this aspect of the phone.

Also, LOL that I can force it to use GSM and only have edge data

Awesome !! And big thanks for this Johnsondr80 !! And a thanks to KevL also !!

Does this mean UL/DL speeds can be improved on those listed modems?

Johnsondr80 said:

Not there yet. But they say 850 is faster due to less users clogging the line.

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Also the 850 Band travels better so you'll see stronger signal more often. Should also give better call quality, tho I'm not 100% on that part.

I just wated to verify.....So there will still be no hspa with the i897 modems... And the same bugs with using a I9000 kernal aply, no buetooth, is that corect? This just alows band selection?

Sent from my GT-I9000 using XDA App

thumper_1151 said:

I just wated to verify.....So there will still be no hspa with the i897 modems... And the same bugs with using a I9000 kernal aply, no buetooth, is that corect? This just alows band selection?

Sent from my GT-I9000 using XDA App

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Yep, I897 modem is still hsdpa only. Yep, does not add any new kernel compatibility. Yep, does allow for band selection (tho still not a easily as those without RAT)


So, it is mainly useful for devs / testers, and ppl who have dumb phones that love using 1900 band during heavy traffic and/or low signal.

I know you guys said this was for testing but I just tried this with the KF1 modem. So I left my self a voicemail, listened to the vm and wow the voice quality sounds really bad. Is anyone else having the same problem?

I have tried this a couple times and it doesn't seem to work for me. RAT is still restricted at the main menu.

jack man said:

I have tried this a couple times and it doesn't seem to work for me. RAT is still restricted at the main menu.

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This does not remove RAT. As Johnsondr sneaks in there "This is really more of a security loop hole!!" In that you can enter the menu with the sim card out and lock in the phone to use your band of choice. When you put the sim back in it stays locked in.

Annoying yes, but at least we now have a means of changing the band when service is generally crappy.

I notice if I reboot my phone it sets back to 1900 again. I made sure to follow the steps correctly three times. Is this how it works?


Cognition V1.0 KF1

Johnsondr80 said:

You must have posted in wrong thread.

sign up for dropbox using this link to get 250mb free and help fusion at the same time.
http://db.tt/cCn3zrY
presented by Xdapremium app

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I'm confused why do you think I posted in the wrong thread. I did your step to get audience chip support. Audience chip is suppose to offer better voice quality. Am I missing something?

did this a couple more times to make sure I went through the steps correctly and both times when going back to the menu to see what band it was on I watched it go from 850 back to 1900. This was without a reboot or any button pushes. I hope we can find something that will work consistantly.

This works, however, it does not stick on reboot.

nappent said:

I'm confused why do you think I posted in the wrong thread. I did your step to get audience chip support. Audience chip is suppose to offer better voice quality. Am I missing something?

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My guess is that your on an I9000 rom and flashed a captivate modem. In which case audio quality will be ummm pretty much gone

Sent from my SGH-I897 using XDA Premium App

nappent said:

I'm confused why do you think I posted in the wrong thread. I did your step to get audience chip support. Audience chip is suppose to offer better voice quality. Am I missing something?

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Maybe you miss read. There is nothing here to give audience chip support to those who don't already have it. OP mentions this is for ppl who choose an I897 modem+kernel so that they can use the Audience chip.