Replicant

If you're looking for information which parts are good for freedom, here is a good place to ask! Generally speaking, here are some recommendations to do things right:

• Make sure the full Linux kernel source can be released
• Pick a platform where all the bootloaders are free software (e.g. iMX, OMAP, Allwinner)
• Disable any signature check on the bootloaders and kernel
• Make UART pins available for easier debugging and flashing when
  working on e.g. a free software bootloader
• Make sure the modem is not part of the SoC and cannot access the
  phone's memory, RAM, GPS and cannot control the audio chip.
• Make sure it is easy to reflash the phone with free software tools
• Make sure the chips use standard protocols (Modem would use AT, GPS
  would use NMEA, etc)
• Make sure the kernel interfaces are standard Linux interfaces (ALSA,
  V4L2, etc)
• Use the ath9k_htc WiFi chipset, which can be embedded in a phone and
  has a free firmware
• Use a platform with a Mali or Adreno GPU, for which we are likely to
  see a working free software implementation in the near future

In order to reliable achieve privacy, a way to disconnect the modem from its antenna is the way to go.

"Use a platform with a Mali or Adreno GPU, for which we are likely to
see a working free software implementation in the near future"

http://tech.slashdot.org/story/14/05/27/0531232/mesa-102-will-feature-better-adreno-driver-openmax-cherryview-support

Paul Kocialkowski wrote:

In order to reliable achieve privacy, a way to disconnect the modem from its antenna is the way to go.

Hello. I tried the antenna disconnection on some cheap android phone and the result is rather discouraging:
even with antenna disconnected the phone was still able to pick up the wifi signal from nearby wifi routers, just with way poorer strength. I had no sim card to test the signal for GSM channel but being in city with lots of cellular towers I think there is a risk that with GSM signal being strong from the outside - the disconnection of external antenna does not make much difference.

So - anyone having any experience with disabling GSM modem really properly? I just something for pocket note taking without any wifi/call functionality. So I carry it with me, take notes and export them through usb wire. There are lots of cheap Android phones to be potentially converted to such 'PDA' format - but it seems there is no reliable way to fully disable all wireless even if one is ready to cut mainboard wires and solder/un-solder stuff?

Any comments?

To "disable" an antenna you could connect it to an earth (or 0v) or transmit noise into it to corrupt what it is receiving.

There is also a thing called a faraday cage, which doesnt sound very practical, but i think its the concept used behind the RFID blocking sleeves used to prevent the theft of credit cards details.

I had no sim card to test the signal for GSM channel but being in city with lots of cellular towers I think there is a risk that with GSM signal being strong from the outside - the disconnection of external antenna does not make much difference.

It would be worth trying with GSM as well, I am uncertain about whether it can still substantially use the GSM network to e.g. transmit data.

So - anyone having any experience with disabling GSM modem really properly? I just something for pocket note taking without any wifi/call functionality. So I carry it with me, take notes and export them through usb wire. There are lots of cheap Android phones to be potentially converted to such 'PDA' format - but it seems there is no reliable way to fully disable all wireless even if one is ready to cut mainboard wires and solder/un-solder stuff?

Well, you could probably just keep it powered off/not booted. I will soon (months) add instructions on how to do that for each device.