I just purchased this phone from ebay and installed a new battery. The Gas_Gauge pin is not plugged in* so I dont know if that matters or not.

Anyway* the phone reboots every 5 minutes or so (only when fully booted into iOS). Here is the kernel panic log
margin: 0px;
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overflow: auto>Incident Identifier: XXXX
CrashReporter Key: XXXXX
Hardware Model: iPhone3*1
Date/Time: 2010-12-16 22:13:11.641 -0500
OS Version: iPhone OS 4.2.1 (8C148)

Debugger message: WDT timeout
0s ago: 2000b50 2000r3ff000 1900m10004003 1800m0 1700m0 1600m0 1500m0 1400m0 1300m0 1200m0 1100m0 1000m0 900m0 800m0 800bff 800t3fe 700m0 600m0 500m0 400m0 300m0 200m0 100m0 0m0
OS version: 8C148
Kernel version: Darwin Kernel Version 10.4.0: Wed Oct 20 20:14:45 PDT 2010; root:xnu-1504.58.28~3/RELEASE_ARM_S5L8930X
iBoot version: iBoot-931.71.16
secure boot?: YES
Paniclog version: 1
Epoch Time: sec usec
Boot : 0x4d0ad422 0x00000000
Sleep : 0x00000000 0x00000000
Wake : 0x00000000 0x00000000
Calendar: 0x4d0ad512 0x0000222d

Task 0x811e8d3c: 6711 pages* 93 threads: pid 0: kernel_task
thread 0xc0a42b20
kernel backtrace: d2f8baf0
lr: 0x80068a91 fp: 0xd2f8bb1c
lr: 0x80068c95 fp: 0xd2f8bb30
lr: 0x802dc217 fp: 0xd2f8bfa8
lr: 0x800672fc fp: 0x00000000

Task 0x811e8b58: 175 pages* 3 threads: pid 1: launchd
Task 0x811e85ac: 606 pages* 4 threads: pid 12: ptpd
Task 0x811e83c8: 181 pages* 4 threads: pid 13: syslogd
Task 0x83e9bd3c: 511 pages* 2 threads: pid 16: lockdownd
Task 0x83e9b974: 1955 pages* 29 threads: pid 18: mediaserverd
Task 0x83e9b790: 332 pages* 3 threads: pid 19: mediaremoted
Task 0x83e9b5ac: 315 pages* 3 threads: pid 20: mDNSResponder
Task 0x83e9b3c8: 898 pages* 9 threads: pid 21: locationd

Task 0x83e9b1e4: 410 pages* 2 threads: pid 22: imagent
Task 0x83e9b000: 399 pages* 1 threads: pid 23: fairplayd.N90
Task 0x83f1ad3c: 627 pages* 14 threads: pid 24: configd
Task 0x83f1a974: 212 pages* 2 threads: pid 26: accessoryd
Task 0x83f1a790: 4447 pages* 16 threads: pid 27: SpringBoard
Task 0x83f1a000: 669 pages* 10 threads: pid 31: CommCenter
Task 0x84053d3c: 348 pages* 3 threads: pid 32: BTServer
Task 0x84053b58: 122 pages* 2 threads: pid 33: notifyd
Task 0x811e81e4: 171 pages* 6 threads: pid 37: SCHelper
Task 0x83f1a1e4: 128 pages* 2 threads: pid 47: afcd
Task 0x83f1a3c8: 147 pages* 4 threads: pid 48: notification_pro
Task 0x893dfd3c: 326 pages* 3 threads: pid 51: apsd
Task 0x84053790: 211 pages* 3 threads: pid 52: lsd
Task 0x893df790: 1278 pages* 4 threads: pid 57: MobilePhone
Task 0x840531e4: 2411 pages* 6 threads: pid 64: MobileMusicPlaye
Task 0x811e8974: 2397 pages* 5 threads: pid 66: Preferences
Baseband logs show: 6:23:50 -0500 ST [rm] reset: reason=+XCGREG triggered dump;uptime=785;count=

Tried restore in DFU and in Restore Mode* but no luck. Any suggestions? I dont know whether or not to think its hardware or software* since sometimes it will start to the connect to itunes screen with IMEI Unknown.