Recover and Repair a Failed Ubuntu Upgrade

I recently upgraded from Ubuntu 10.04 LTS to Ubuntu 10.10 - it didn't go quite to plan! Midway through the upgrade the GUI (Gnome Desktop in my case) froze and I had to power off manually and restart.

All I got was the usplash screen and when I Alt-Ctrl F1 'd i saw "mountall: disconnected from plymouth". No matter what I tried couldnt get any further.

It happened to me once before and in the end I reinstalled which wiped everything. Now I'm a little more seasoned I knew this wasn't going to be necessary.

So I used my 10.04 LTS liveCD and started searching for solutions. I managed to find the following info which poved most useful because it allowed me to mount my HDD FS within the liveCD GUI and work from cmd line as though I were in the HDD OS: http://ubuntuforums.org/showthread.php?t=422523

Also quite useful:

http://galigio.org/2009/11/29/how-to-repair-a-bad-upgrade-on-ubuntu/

http://serverfault.com/questions/8540/recover-from-shutdown-during-ubuntu-distribution-upgrade

http://ubuntuforums.org/showthread.php?t=186672

http://www.ubuntugeek.com/easy-way-of-mountunmount-iso-images-in-ubuntu.html (used this to download and mount the alternate upgrade cd, which is how I eventually fixed my upgrade)

Essentially what had happened was that after usplash the nvidia drivers werent loading, so I removed the xorg.conf file, and replaced it with the xorg.conf.failsafe. This step got me booting into a low res gnome desktop, yaaay!

I then Alt-Ctrl F1 'd to the shell, and mounted the ubuntu-alternate iso I had downloaded when I was in the liveCD, and which I ha copied to my home folder on my HDD from there.

Once the iso was mounted I simply ran:

sudo /media/cdrom/cdromupgrade

and ten minutes later everything was fixed and my desktop was up and running 10.10 !

Good Luck! :)

Clean your MAF sesnor for smoother running and better fuel economy

Ive just cleaned the MAF (Mass Air Flow) sensors on both of my cars. An easy procedure which, has produced smoother running, instantly noticeable better fuel economy, and more power at low revs.

I was apprehensive about doing that, as a mechanic friend of mine, whom I trust a lot, told me it wasn't a good idea, but having read around the subject and watched a few youtube videos, I was confident I could do it and that it was a good idea - or at least time would tell!

Now the cleaning solution I wanted to use (CRC Mass Air Flow Sensor Cleaner) wasn't available officially in England due to EU laws on chemicals or something or other, so I went for the next best thing (or just as good).

Maplin, sell Isopropyl Alcohol in a pressurised can, which has pretty much the same desired effect as the CRC product I believe from my googling.

The theory is that the isopropyl alcohol is safe for electronic components and contact, and it removes dirt, grease, grime, etc which is exactly what we want to do. The hot wire in the MAF runs at around 200 degrees Celsius and when air passes over it, small particles like pollen and dirt, hit it and then 'cake' themselves on, leaving a 'dirty' residue which reduces the efficiency of the MAF and fools your engine ECU into using the wrong air/fuel mix, giving you less economy, and even worse, less power to go with it.

Caution: the MAF is an extremely sensitive piece of equipment, and the hot wires are extrmemly brittle. If you drop or knock the unit you may break it, and this will set you back hundreds of pounds, so be careful!!!

Having bought a can, I whipped out the MAF sensors on both cars (about 10min job each - make sure car is COLD before you do this) and proceeded to clean as per some of the videos I had seen around the CRC product. 

Basically spray at the hot wire, and only the hot wire. Short one second bursts around five seconds apart, just as a rough guide. Continue until shiny and clean, which should require no more than a dozen or so bursts, even for the dirtiest hot wires. I blasted mine from all different angles not just one, so as to get the hot wires totally clean.

The result? Well, the BMW's hot wire started off a golden brown colour and was restored to sparkling silver. The Toyota hot wires were actually black! after 30 seconds, they were gleaming silver! Job done. I waited till the alcohol had dried completely (if I couldn't smell the vapours anymore then it was done). Then put both MAF's back on the cars.

The BMW felt a bit spongy when I took it for a test drive, which made me think I'd bricked the MAF, but after a couple of miles it came to life and I saw the estimated range shoot up on the on board computer display. The car felt much, much smoother, much more power at lower revs. Lovely!

Same story with the Toyota. I guess, the ECU's had to self learn and adjust the paramteres of the air/fuel mix and this takes anywhere from a couple to 15miles to do depending on your car and the type of ECU.

All in all, both cars feel a lot smoother, more torque at low revs, and way more fuel economy. As a rule I think I will do this every 20,000 miles or so.

Peace