Phone always off: Wireless radio off

[pook13]

I did downgrade my radio from 3.42.50 to version 1.x using SPL 0.41
like someone's thread on xda to get standalone GPS.
Now I have an issue, seems like as u said, some portions of radio aren't overwritten.here some symptoms I got :
1. when booting, WM6 said "Phone Off". in comm manager its status is Flight mode. when I turned on the phone, a pop up shown "Phone is off, do you want to turn it on?" I press yes, but the radio shown no signal. when I tried to make call, phone was turned off again. Can't make any calls at all.
I try with some of official and customize rom.Result is the same.

2. when I enter EPST ##778 and make some changes and then press OK, it said "Turn on LPM failed. Press OK to reset device".
Software and Firmware version can't change
It still 3.09.666.1 and radio rom is 3.42.50.
CDMA setting/EPSt show the item "EVRC enabled" is out of range.
EVRC Enabled: Disabled
Home page: Wild
Home Orig: EVRC
Roam Orig: .......
Can't change anything...It will stop with Written Item "..." error

3. when I use QPST to make PRL changes then press Write to phone, the gauge bar showed 100% but then the device automatically reset (soft). The QPST then showed message something like "Writing process not finished".Same problem shown when I tried to back to 3.42.50 with SPL 2.31.

So, any ideas to help this noob?
Thanks a lot

I am quote this word form
edimonoarfa
http://forum.ppcgeeks.com/showthread.php?t=26082
Dangers of downgrading after installing GPS radio (and a little on signing)

Please help me...
I try to solve this problem for a week.
I read in this forums and xda.., I couldn't find the solution.

Right now,
Everything work well,
EPST is work well after I follow instruction from "horndoctor"
Except it can't turn on the phone
Phone sign shows in No Service.

Phone still off, and can't get it on