Wifi problems with Elementary OS Freya on the ideapad 100

This week I had a problem where wifi suddenly stopped working on my Lenovo ideapad 100 15iby running Elementary OS Freya. I don't know what happened, but suddenly the machine refused to work with any access points. It would say I was connected, and I would have an IP address from DHCP... but there was no actual connection working. Chrome would just complain there was no internet, for example.

I ended up having to rebuild the Realtek rtl8723be wifi driver from the source repository here: https://github.com/lwfinger/rtlwifi_new/ but actually that was not too bad, because the instructions are quite simple. I just had to follow this post which seemed to work fine for me. But I did need to disable the sleep feature of the driver, which is mentioned as an extra step in the instructions. Otherwise the connection would keep dropping and then prompting me for my wifi password all the time.

So that was a slightly annoying problem! But I am pleased to have it sorted out. As I'm writing this I'm downloading a 750Mb file to make sure it's all OK. I'm currently at 500Mb and all is fine, so hopefully that's a job well done.

I have also noticed that Elementary OS Loki is now released, but there is no upgrade route from Freya, so I need to find some free time to do a backup and clean install. Hopefully that will be a smooth process... maybe I'll try running it 'live' first, without installing, to make sure that things work beforehand. That's a job for another day.

Enhancements to the DR-DOS boot stick

I've made a few enhancements to the DR-DOS boot stick that I made, so here are the details. Just copy the files mentioned to the root of the boot disk.  I believe that everything used is free for non-commercial use.  Here goes:

The OAKCDROM.SYS generic CD-ROM driver (will work with most IDE CD-ROM drives) I got my version from here. Open the zip file and look inside the "Floppy" subfolder.  Just copy OAKCDROM.SYS to the boot disk.

In addition to the CD-ROM driver, I've used a MSCDEX replacement called SHSUCDX, which is linked to from here.  I've downloaded the "shcdx33e.zip" version. Just copy the SHCDX33E.COM file to the boot disk.

For memory management I've added two things:
  HIMEMX - copy both EXE files
  CWSDPMI - just copy CWSDPMI.EXE (in the bin folder)

And finally, I've added a RAMdisk driver... we need to copy the SRDISK.EXE and SRDXMS.SYS files.

To get all those files to work we also need to edit AUTOEXEC.BAT and CONFIG.SYS:

AUTOEXEC.BAT
-----------------
CWSDPMI
SHCDX33E /d:CD001 /l:X
SRDISK 10240 /E
%SRDISK1%:

CONFIG.SYS
--------------
LASTDRIVE=Z
DEVICE=himemx.exe
DEVICE=OAKCDROM.SYS /D:CD001
DEVICE=SRDXMS.SYS

So now if we boot from the memory stick we'll have X: mounted as the CD-ROM (if you have one) and the current drive will be an empty 10Mb RAM drive.  We also have better memory management.  It should be a reasonable DOS system, and to the best of my knowledge everything I have used is free for non-commercial use - good for the hobbyist that wants to run a DOS machine.