Non-branded ES400 Sprint Firmware installation

If you're using a non branded ES400 (i.e. not a "sprint" or "Verizon" ES400) than a firmware upgrade is needed to make the Sprint cell data service to work on a non-branded ES400.

1. Utility to unlock ES400 from AT&T service. Phone is locked when a sim card is inserted.

http://support.symbol.com/support/search.do?cmd=displayKC&docType=kc&externalId=12957&sliceId=&dialogID=258812027&stateId=1 0 258810118

2. If the ES400 is the newer B models with the new radio that’s switchable, the latest version is:  02.31.0002 which has a release date in Oct, 2011.

Here is a link for the firmware needed for Sprint service (note ROM upgrades are destructive)

http://support.symbol.com/support/search.do?cmd=displayKC&docType=kc&externalId=13325&sliceId=&dialogID=252742305&stateId=1%200%20252740311