Waiting for /dev/sda1 to appear... failed, ignoring. Waiting for /dev/sda2 to appear... failed, reverting to /bin/bash
This message indicates, either the device files for sda were not created or the device itself was not initialized. Usually this happens due to the disk modules not being loaded.
Make sure the modules required for your disk to work are loaded. I do not know what type of disk you have, I can't tell you for sure what modules you would need. Once the right modules are loaded, the disk should be recognized and initialized. After that it is just udev creating the device files for the disk followed by the root partition being mounted.
If you downloaded/installed a kernel patch, it could have resulted in some sort of version conflict or symbol missing/mismatch or otherwise.
I normally do not use the precompiled kernel so, I've never faced this situation. It would be worth while to compile your own kernel and install it. Whenever security fixes/patches become available, you can download the kernel sources or the source diffs and compile a fresh kernel.