Can't switch between b/g/n

[2confused]

One of the local free wifi spots only allows g/n. My laptop is only allowing me to use b, for some reason...aka I can't get online from that particular library. The same it seemed like I started having trouble getting online there I also noticed my entire internet connection seemed to slow down at other locations. This was 9-12 months ago that this happened. I'm still able to get online and still notice at times what seems like a slower connection. I know in checking, earlier this year, that the computer doesn't want to indicate which mode(b/g/n) it is connected with. The only way I can tell anything is by looking at the speed of the connection and that does want to indicate it must be connecting with b. How do override the setting so it will to connect with g/n.

I'm using Mint 18.1 with a broadcom 43142 wifi card.

When I go the terminal and type in
inxi -Fxz
this is the response I get back

• System: Host: Someone-Somewhere Kernel: 4.4.0-78-generic x86_64 (64 bit gcc: 5.4.0)
  Desktop: Cinnamon 3.2.7 (Gtk 3.18.9-1ubuntu3.3)
  Distro: Linux Mint 18.1 Serena
  Machine: System: HP (portable) product: HP Stream Notebook v: Type1ProductConfigId
  Mobo: HP model: 815E v: 32.0C Bios: Insyde v: F.04 date: 09/21/2015
  CPU: Dual core Intel Celeron N3050 (-MCP-) cache: 1024 KB
  flags: (lm nx sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx) bmips: 6402
  clock speeds: max: 2160 MHz 1: 1554 MHz 2: 1978 MHz
  Graphics: Card: Intel Device 22b1 bus-ID: 00:02.0
  Display Server: X.Org 1.18.4 drivers: intel (unloaded: fbdev,vesa)
  Resolution: 1366x768@60.00hz
  GLX Renderer: Mesa DRI Intel HD Graphics (Cherryview)
  GLX Version: 3.0 Mesa 11.2.0 Direct Rendering: Yes
  Audio: Card Intel Device 2284 driver: snd_hda_intel bus-ID: 00:1b.0
  Sound: Advanced Linux Sound Architecture v: k4.4.0-78-generic
  Network: Card: Broadcom BCM43142 802.11b/g/n driver: wl bus-ID: 02:00.0
  IF: wlo1 state: up mac: <filter>
  Drives: HDD Total Size: NA (-) ID-1: /dev/mmcblk0 model: N/A size: 31.3GB
  ID-2: /dev/mmcblk1 model: N/A size: 31.9GB
  Partition: ID-1: / size: 26G used: 24G (97%) fs: ext4 dev: /dev/dm-1
  ID-2: /boot size: 473M used: 114M (26%) fs: ext2 dev: /dev/mmcblk0p2
  ID-3: swap-1 size: 2.00GB used: 0.05GB (3%) fs: swap dev: /dev/dm-2
  RAID: No RAID devices: /proc/mdstat, md_mod kernel module present
  Sensors: System Temperatures: cpu: 38.0C mobo: N/A
  Fan Speeds (in rpm): cpu: N/A
  Info: Processes: 186 Uptime: 30 min Memory: 1221.5/1859.6MB
  Init: systemd runlevel: 5 Gcc sys: 5.4.0
  Client: Shell (bash 4.3.481) inxi: 2.2.35

When I type in
lspci -vnn | grep 14e4

• 02:00.0 Network controller [0280]: Broadcom Corporation BCM43142 802.11b/g/n [14e4:4365] (rev 01)

When I type in
iwconfig

• lo no wireless extensions.
  
  wlo1 IEEE 802.11abg ESSID:"McDonalds Free WiFi"
  Mode:Managed Frequency:2.412 GHz Access Point: 00:14:6A:C5:8D:30
  Retry short limit:7 RTS thr:off Fragment thr:off
  Power Management:on

When I try
sudo iwconfig wlo1 modu 11g

• Error for wireless request "Set Modulation" (8B2F) :
  SET failed on device wlo1 ; Operation not supported.

When I try
iwlist wlo1 scan | grep Frequency | sort | uniq -c | sort -n

• 1 Frequency:2.412 GHz (Channel 1)

I'm not sure if that is suggesting only one channel to work with or what. Just trying to provide as much information as possible that I think may be asked for. I know in the past I thought I have seen a whole list of channels but when I tried switching to them I always came up the 'Operation not supported' error.

What else do you need to know. I know I probably won't be back online until sometime tomorrow. Not sure when though. Figured I would get this posted while it is on my mind.