from personal experience, T-Mobile validates devices via the said devices' IMEI.
FOR EDUCATIONAL PURPOSES ONLY!!!
- Doing anything im posting here IS against T-Mobile's Terms of Contract! And another thing, when you bought your phone the papers you may have signed included (in fine print) that: "T-Mobile has the right at anytime to re-apply the proper data plan ($30 one) at any time, if the user choses to remove it)
So basically, what i am about to tell you is against t-mobiles contract, they can replace it with $30 dollar data, and for EDUCATIONAL PURPOSES ONLY!
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What i had to do was pop my sim card into a razor (or any non-smartphone) for an ENTIRE 24 HOURS before calling T-MOBILE, i then contacted them saying my cliq has malfunctioned, and i would like to replace my data plan. BE SURE to tell them that "in past experiences, ive had to give a customer service rep my IMEI (of the nonsmartphone) for it to work, so can i give you it?" If the customer service rep does not accept it tell them that you will callthem back, because "in past experiences it did not work without giving them said information".
After you have given them the nonsmartphone's IMEI, and have changed the data plan, USE THE NON-SMARTPHONE for an ENTIRE 24 hours, atleast! Even if the data plan works!
After a day or two, replace the sim card back into your android device, and it should work.
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DO NOT change APNS! DO NOT use the "voicestream" APN, because it has since been shut down (only for MMS purposes).
T-Mobile ONLY uses "epc.tmobile.com" as their APN for ALL devices and ALL data plans, it should work.
****This will most likely not work for a long time, considering, T-Mobile's towers validate the IMEI's on a pretty consistant basis, to ensure that this does not happen.
I am currently using this on my CLIQ, and i DO have 3G speeds. I am currently tethering without a problem.. soo.. nothing changes.