I want to use a t mobile sim card in a motorola i855 boost phone

You can get the unlock code here mobileunlocksolutions.com and also get the unlock instruction in the same site....

Yes it should if the LG mobile phone is unlocked. If not, when you insert the Boost SIM card in the LG it will ask for a Secutity Code.
If the SIM card won't work in the LG, please get back to me.

Remove the battery from the phone. Let it remain out of the phone for 10 minutes with the phone off. Replace the battery and turn the phone on.

This is a problem with the phone trying to read the SIM card after being in another phone. Be patient. It may take several minutes for the phone to read the SIM.

When you place a new or SIM card from another phone provider from the original phone contract then it asks for a Security code.
Your phone is locked to this mobile phone provider. You need to contact this mobile provider to ask for the unlock code (security code) for your phone. You need to provide proof of ownership etc and the phone's unique IMEI number which is located inside the phone under the battery. They use this number to generate the unlock code for your phone.
They should provide you with instructions on how to enter this code into the phone.
Once you unlock the phone, then you can insert a new SIM card in the phone.

Turn the phone off. Take the battery out. Let it stand without the battery for 10 minutes. Install the battery and turn on the phone.

This problem is with the phone recognizing the SIM card. It may take a few minutes for the phone to recognize the SIM. Just be patient.

it can not work at all, boost mobile uses IDEN which is different from GSM. even if you unlocked the phone it won't work , sorry

If this your motorola i855e is a Nextel phone, then not all the features will work very well if you put in a Boost Mobile sim card. Features like Texting, Web browsing are not likely to function very well or at all. Get a Boost phone for a Boost sim card. Cheers.

I called Boost support about the same issue and I was told that that particular phone and any other Ic series phone by motorola will not work with Boost Mobile. There was also a few other phones that will not work. Try calling thier support line and requesting the list of phones that won't work. Good luck.

boost only uses boost sim cards
you cant put in a nextel sim in a boost phone
call customer service

If this phone was originally a Boost phone, it is more then likley on the IDEN network, which is exclusive to Nextel/Boost. Once the new SIM from the company other then Nextel/Boost is put in the phone, it will ask for a special code- thus rendering the phone useless on the new network. IDEN is only used by Nextel/Boost and another company out of the South called southernlinc.