The modification I present here comes from this thread.
So far tested on: miniCM RC1, CM7 RC4
1. We go to /system/etc/firmaware directory and find files named:
/etc/firmware/fm_rx_init_1273.2.bts /etc/firmware/fm_tx_init_1273.2.bts /etc/firmware/fmc_init_1273.2.bts
3. Go back to /system/etc and find a file named tiwlan.ini
NOTE: In CM7 based ROMs the path may be /system/etc/wifi
4. Look for the following lines:
HT_Enable=0 #0=diable 802.11n support / 1=Enable BurstModeEnable = 0 # 0 - Disabled 1 - Enabled WiFiAdhoc = 0
HT_Enable=1 #0=diable 802.11n support / 1=Enable BurstModeEnable = 1 # 0 - Disabled 1 - Enabled WiFiAdhoc = 1
Look for the line:
Single_Dual_Band_Solution = 0
Single_Dual_Band_Solution = 1
Troubleshooting: If after enabling your wifi keeps disconnecting, or you get the "connecting" bug, go to settings->networks->wifi, erase all remembered networks and reboot.
Disclamer: if you crush your wifi or brick your phone, I'm not responsible for it.
5GHz band and AdHoc features need testing to prove they work, N standard 100% working.
Also, I've been told that each ROM has different tiwlan file - if it's so, then we need custom zip for each ROM available. I'm not familiar with how it's done, so if someone could prepare them I'll attach them to the first post
Enjoy, X8 users!