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if you pay the google tax for a pixel, you get a convenient 2G toggle. if you don't have an extra $400-900 and buy a cheaper android, you get to dial ##4636##

if you pay the google tax for a pixel, you get a convenient 2G toggle. if you don't have an extra $400-900 and buy a cheaper android, you get to dial ##4636## (hn screws asterisks, look it up) them go into phone info, select each sim radio and change the drop down (and hopefully you know all the standards by all names to make the right choice. hint 5G is NR there)

toast0 2y ago
There's a convenient toggle on my Moto G Stylus 5G 2023, if not a convenient name. In the carrier settings right next to allow 5G. Can't easily disable 3G or LTE though. IIRC, LTE is also mutually authenticates, but if we're talking about passive catching and the ismi is sent in the clear as the article says, then that doesn't eliminate passive catching. I'm not sure about 3G, I thought it wasn't mutual auth either.
- lxgr 2y ago
  Definitely, mutual authentication and (not) using long-term identifiers in the initial attach request are largely orthogonal concerns. I believe even 3G supports mutual authentication (at least if the SIM supports it, i.e. it’s not a very old GSM only one), but anonymized identifiers only appeared with 5G.
- 1oooqooq 2y ago
  wait. which market? never seen a Motorola with the "disable 2G" toggle! and yes, that only prevents the lower denominator which uses downgrade, which is the vast majority everywhere.
  - toast0 2y ago
    US market, purchased direct from Motorola.
Bender 2y ago
One can backslash escape the asterisks. ** \*\*
- 1oooqooq 2y ago
  kinda of information that would be very useful displayed when you're entering a comment. it's not like i work here...
  - Bender 2y ago
    That and all the things listed in this repo [1] not my repo. [1] - https://github.com/minimaxir/hacker-news-undocumented https://github.com/minimaxir/hacker-news-undocumented
JadeNB 2y ago
> ##4636## (hn screws asterisks, look it up) You can include asterisks if you escape them, like \*: *#*#4636#*#*.
jeroenhd 2y ago
The 2G toggle can also be found in some other phones, but not every phone manufacturer has support for configuring their modems like that or has bothered to keep the setting in their settings app overhaul. I know that setting, but I'm not entirely sure if that controls a preference or a mandatory cell config, and if it will prevent downgrades from the network side or not. Some manufacturers and most custom ROMs also seem to offer that option without a dial code, but I haven't found any documentation about that feature yet to be sure it actually forces the modem configuration. I've found mentions online about this setting being changed without user interaction, so there seems to be a mechanism on some phones (carrier-branded ones maybe?) that alters this config.
- 1oooqooq 2y ago
  every modem have to have that control. and you can access it on every model I've ever seen with the code i shared. i think it might be a requirement for some of the regulations they plaster stickers for. having the ui it not is a balance between playing nice with over reaching law enforcement and enterprise clients.
elric 2y ago
Is there a name for those ##number## codes? It's been years since I had to use one of them to fix some random issue on a phone.
- taneliv 2y ago
  USSD and MMI, see for example https://en.wikipedia.org/wiki/Unstructured_Supplementary_Service_Data https://en.wikipedia.org/wiki/Unstructured_Supplementary_Ser... . On a quick glance the references did not seem to list what codes are usually available, so just search "ussd code list" or similar.

toast0 2y ago

There's a convenient toggle on my Moto G Stylus 5G 2023, if not a convenient name. In the carrier settings right next to allow 5G. Can't easily disable 3G or LTE though. IIRC, LTE is also mutually authenticates, but if we're talking about passive catching and the ismi is sent in the clear as the article says, then that doesn't eliminate passive catching. I'm not sure about 3G, I thought it wasn't mutual auth either.

lxgr 2y ago
Definitely, mutual authentication and (not) using long-term identifiers in the initial attach request are largely orthogonal concerns. I believe even 3G supports mutual authentication (at least if the SIM supports it, i.e. it’s not a very old GSM only one), but anonymized identifiers only appeared with 5G.
1oooqooq 2y ago
wait. which market? never seen a Motorola with the "disable 2G" toggle! and yes, that only prevents the lower denominator which uses downgrade, which is the vast majority everywhere.
- toast0 2y ago
  US market, purchased direct from Motorola.

Bender 2y ago

One can backslash escape the asterisks. ** \*\*

1oooqooq 2y ago
kinda of information that would be very useful displayed when you're entering a comment. it's not like i work here...
- Bender 2y ago
  That and all the things listed in this repo [1] not my repo. [1] - https://github.com/minimaxir/hacker-news-undocumented https://github.com/minimaxir/hacker-news-undocumented

JadeNB 2y ago

> ##4636## (hn screws asterisks, look it up) You can include asterisks if you escape them, like \*: *#*#4636#*#*.

jeroenhd 2y ago

The 2G toggle can also be found in some other phones, but not every phone manufacturer has support for configuring their modems like that or has bothered to keep the setting in their settings app overhaul. I know that setting, but I'm not entirely sure if that controls a preference or a mandatory cell config, and if it will prevent downgrades from the network side or not. Some manufacturers and most custom ROMs also seem to offer that option without a dial code, but I haven't found any documentation about that feature yet to be sure it actually forces the modem configuration. I've found mentions online about this setting being changed without user interaction, so there seems to be a mechanism on some phones (carrier-branded ones maybe?) that alters this config.

1oooqooq 2y ago
every modem have to have that control. and you can access it on every model I've ever seen with the code i shared. i think it might be a requirement for some of the regulations they plaster stickers for. having the ui it not is a balance between playing nice with over reaching law enforcement and enterprise clients.

elric 2y ago

Is there a name for those ##number## codes? It's been years since I had to use one of them to fix some random issue on a phone.

taneliv 2y ago
USSD and MMI, see for example https://en.wikipedia.org/wiki/Unstructured_Supplementary_Service_Data https://en.wikipedia.org/wiki/Unstructured_Supplementary_Ser... . On a quick glance the references did not seem to list what codes are usually available, so just search "ussd code list" or similar.