[Q] WiFi setting still in phone after flashed with new ROM
I am new here, and this is my First post,
I am running stock ROM 4.03 (I9100MUGLD3_I9100MBMCLD3_BMC), I did a "wipe data/factory reset" and then update the new ROM 4.12(I9100MUGMA5_I9100MOYCMA5_BMC) by Odin 3.04.
In this case, my phone should be wipe and has a new fresh look and my setting should be all gone. but I found out my WiFi connection for work still list inside my phone, and when I back to work, the WiFi connected automatically.
so, I tried again, wipe data/factory reset, flash it back to above Original Bell ROM 4.03 (I9100MUGLD3_I9100MBMCLD3_BMC), when I back to setting, my company SSID still in the phone. so I root the phone and wipe data/reset, then flash it to (SuperNexus-2.0-i9100-BUILD1) by using the MicroSD Card. my company SSID is gone, so I did a wipe data/reset, then flash it back to 4.12(I9100MUGMA5_I9100MOYCMA5_BMC) by Odin 3.04. again, my company SSID come back in my wifi list. and when i back to work, wifi connect again.
is there something I didn't do it in the right way to flash a new ROM?
or how do I completely erase EVERYTHING in my phone, in case I give my phone to someone else?
also, after I flash to different ROM's(GalaxyMOD_XWLPX_v3.01_by_AJ, BestS2ROM v1.1, Galaxy S2 I9100XWLS8 (4.1.2) - Spain, I9100XWLSD_I9100OXXLS6_I9100XXLS8_NEE), the serial number of my phone became PPPPP, but when I flash it back to Stock ROM, my serial number back to normal. does anybody else have the same issue?