Common rom installation problems and what to do about it.

[Guest twrock]

So you can't seem to get that modified rom to install or work correctly. Either it won't boot, or, if it does boot, it doesn't have the Google apps you want, particularly the Android Market app. Maybe this will help you figure out what is going on.

Each official rom has a set size in a partition in its memory called /system. This is where the apps that come with the rom are installed. But the official roms vary in the size of /system. Of course the official roms have enough space for all the apps they put into that particular rom, because that is what Huawei does.

However, modified roms like the ones you find in this forum, might have too many apps (too large in total size) to fit into the /system space made available by the partitioning structure of the official Huawei rom update you installed first.

Additionally, some of the modified roms here don't even include any of the Google apps, including not having the Market app. For example, the original CyanogenMod roms don't include any Google apps, which means they don't have apps like Gmail, Maps, or the Market.

Speaking of the CyanogenMod roms, they do something even more complicated: they temporarily move apps out of /system while installing the base rom and then copy them back into /system at the end of the rom installation process. You might imagine that all those apps can overfill /system very easily.

Finally, some of the modified roms here do not delete everything out of the /system partition before attempting to install their own apps there. This means that you might end up with far too many apps to fit.

When one of these problem scenarios happens, typically the Market app will not be installed correctly or at all. [it is only my guess that this is because the actual file name of the Market app is Vending.apk, so it come late in the alphabet, but I don't know this for sure.] But if the problem is even more severe, other apps or files needed to get your rom running won't be installed, and you won't even get the rom to boot at all.

So what to do?

Once you understand the possible problems, the possible solutions will emerge.

• First, get in the habit of doing a full "wipe data/factory reset" in Clockwork Recovery every time you are going to install a new rom. You'll be amazed at how many problems just seem to disappear when you do that first. [Oh, and notice that I talk about "Clockwork Recovery", not some other Recovery.]
• If the problem is a lack of space in /system, you need to either reduce the total size of the apps being installed into /system or increase the size of /system. Reducing the size of the apps means you will need to learn how to modify the rom yourself. [You probably don't want to take the time to do that, so read on.]
• In order increase the size of the /system partition, you need to first install one of the official rom updates from Huawei that has a larger /system partition. If my memory serves me correctly, the old Hungarian rom, Tre rom and CHT rom have very large /system partitions. The UK rom from back in 2010 has a smaller /system partition than the previous three, but it is still larger than the UK rom from 2011 which has the smallest. [if someone knows more about the different rom partition sizes, please post that.]
• Particularly if you are installing a CyanogenMod rom, consider that you might solve your problem by first formatting the /system partition so that nothing is retained from your previous rom to fill up the space you need for the new CM rom's /system partition. You can format the /system partition in Clockwork Recovery under "mounts and storage".
• If you are installing a CyanogenMod rom, or someone's modification of a CM rom, you will probably need to find a matching "gapps" (which is short for "Google Apps") installation file before you will have access to the Market or other Google apps. Typically the person who modified the rom will link to the file you need, but you might have to ask. And typically you should flash the appropriate gapps right after you flash the CM rom, before you boot for the first time.

And as always, remember to do a Nandroid backup before doing any work on your rom.

Edited August 30, 2011 by twrock