Quote:
Originally Posted by no2chem
Regarding ESN changing being illegal, see : http://frwebgate.access.gpo.gov/cgi-...=2002&TYPE=PDF
I am in the process of getting some letters typed up to get the FCC to change this outdated law which really serves no purpose. Interestingly, 47 CFR 22.919 makes it illegal for a phone manufacturer to update the firmware, see 47 CFR 22.919(c) in relevant part:
"Cellular mobile equipment must be designed such that any attempt
to remove, tamper with, or change the ESN chip, its logic system, or firmware originally programmed by the manufacturer will render the mobile transmitter inoperative." (emphasis added) |
Wow.. Where to start.. I was reading this, wondering what n00b was going to go so far as saying a firmware update was illegal, and then realizing it was no2chem, WTF?! You should know better.
You need to read the ENTIRE section, not just part of a sentence, you're missing a KEY portion.
Quote:
(c) The ESN must be factory set and
must not be alterable, transferable, re-
movable or otherwise able to be manip-
ulated. Cellular mobile equipment
must be designed such that any at-
tempt to remove, tamper with, or
change the ESN chip, its logic system,
or firmware originally programmed by
the manufacturer will render the mo-
bile transmitter inoperative.
|
The purpose of that section was to eliminate/reduce cloned ESNs, and it CLEARLY states that any attempt to change '.. the ESN chip, it's (the ESN chip) logic system...' etc MUST render the mobile transmitter inoperative. You forget that phones made when the law was put in place used PROM/EPROM/EEPROM to store data, not hooked up to some snazzy computer with a USB cable and hacked software. Firmware INCLUDED things such as tuning data, frequency and channel assignments, and the ELECTRONIC SERIAL NUMBER. The LAW says that should the ESN storage system be modified or removed, that it DISABLE the transmitter, Ie it won't work on the network. The way it was implemented in most systems was a checksum, a value derived from the known value created by the ESN. The ESN changes, and therefore the checksum is no longer valid, hence, the device enters into a 'dumb' mode, where it does nothing, meeting the requirements of the FCC to disable the transmitter when the ESN is changed. Obviously equipment manufacturers needed ways to program the phones, so they knew how to change the ESN while changing the checksum as well, that info inevitably leaks out, and 'hackers' reverse engineered the phones to see how things worked...
.....All this before TDMA/CDMA/GSM even existed......
AMPS (Analog Mobile Phone System) was the name of the game back in the day, which is what the laws were aimed at, at the time.
- FCC licensed tech.