Thanks to diekastro's post #8 at the
XDA HTC One X Forum, I found this allowed me to activate a wireless hotspot and eliminated the AT&T check, using SQLite editor.
-- albeit not for the faint of heart:
Make a backup of telephony.db (in case this doesn't work for you)
Your internet APN should be configured (Settings - Mobile data - Access Point names)
1)Open Telephony.db (flange files: data/data/com.android.providers.telephony/databases)
2)Select 'carriers'
3)Search second row, then select Edit field
4)Change ID field with a number non used in this db (ex: in my case the last row is "37" so I used "38") - Save
5)Repeat the 3 and 4 steps, but using row 12.
6)Search the last line (or line with your carrier internet APN)
7)Select the row and Edit Field.
8)Change the ID field to "2". - Save
9)Chose the second row, then Clone Record and change ID field to '12' - Save
Now just need to make changes on the newly created lines:
Row number 2 -> Edit field
1)Change name to ATT Phone
2)Change Type to "default"
2)Insert_by field to "internal".
3)State to "readonly"
Row number 12 -> Edit field
1)Change name to Entiltlement
2)Change Type to "entitle"
2)Insert_by field to "internal".
3)State to "hidden"
My phone: HTC First, rooted and s-off. Stock rom w/ JMZ Kernel. Straight Talk SIM (AT&T network)
--Good luck