Samsung S4: Ad-Hoc WiFi (IBSS) on LineageOS 14.1
I did some investigations into Mesh Networks few weeks ago, in which I set up an Ad-Hoc WiFi network on my Samsung S4 phone.
However, I used CyanogenMod 11, which is a little outdated.
I've received an e-mail from Andrew Hunter email@example.com from Texas, who tried to run an Ad-Hoc network on the current LineageOS, 14.1.
For some reason, CyanogenMod decided to drop support for Ad-Hoc, so the current LineageOS doesn't have it.
In fact, you won't be even able to see Ad-Hoc networks on the network list. They are filtered out.
So he tried to establish a connection by directly calling the Linux command in the adb shell ($SSID can be TestAdHoc and $FREQ 2412 for example):
$ iw wlan0 set type ibss $ iw wlan0 ibss join $SSID $FREQ
However, this results in an error message:
command failed: File table overflow (-23)
For some reason we need a special firmware for the WiFi chip.
Andrew had this problem and asked me if I knew any details on how to fix it.
Well, I didn't. But after several trials and errors he made great progress and got it running!
Luckily, the IBSS firmware is part of the LineageOS image and already on the phone. In order to load it, open up a shell on your rooted phone:
$ adb shell jfltexx:/ $ su jfltexx:/ #
Now open the network view on the phone and disable WiFi.
Execute the following commands:
# WiFi should be down already, just make sure it is ifconfig wlan0 down # Load the correct firmware files for WiFi Ad-Hoc (IBSS) echo "/system/etc/wifi/bcmdhd_ibss.bin" >> /sys/module/dhd/parameters/firmware_path echo "/system/etc/wifi/nvram_net.txt" >> /sys/module/dhd/parameters/nvram_path # Start WiFi again and assign a static IP address ifconfig wlan0 10.0.0.1 netmask 255.255.255.0 up # Set mode to WiFi Ad-Hoc (IBSS) iw wlan0 set type ibss # Join or create the network iw wlan0 ibss join $SSID $FREQ
The new WiFi with the SSID should now show up on other devices when you scan for open networks.
Thank you Andrew for the work you put into this and for sharing the knowledge!
1. Why did it work on CyanogenMod 11?
thinktube.com created patches for CM 11 and 12. These patches included a GUI to select/create a WiFi Ad-Hoc network, but also patched the bcmdhd driver. Please check their page here for details:
It would also be very interesting to know the reasons for the dropped support of Ad-Hoc in newer versions of CyanogenMod/LineageOS. Most likely, thinktube.com just didn't provide patches.
2. List of firmwares
I've used lineage-14.1-20171206-nightly-jfltexx-signed.zip