[Droid Incredible Q&A, Help & Troubleshooting] hachamacha:
Ben,

That's the way it is due to amazing silly usage of resources by HTC in the Incredible. du ./system = 260M and that's it. If you're using the stock system, then it just happens to add up to about ~7M free. Unless you're going to reapportion all the initial partitions, then you can't do anything about it.

All the ROMs are the same unless they've made radical changes, but all the ROMs will have different amounts of free out of the 260M.

If you want to 'fix' it, then you've got all you need if rooted and have TB. Just use ADB or a terminal emulator to do something along these lines (being careful and taking notes so you can retrace the steps if needed):

1) su ; mount system r/w (you can tell which partition it is using 'df' or 'mount' command from a shell and it is of type yaffs2

2) cd /system/app ; ls -l *[Hh][Tt][Cc]* ; ls -l *[Ss][Ee][Nn][Ss][Ee]* and check out which are kind of sizable. All you care about is stuff that is under ./system/... because things like handcent and other userspace apps are really in /data/app, and have nothing to do with this problem.

3) When you locate a few (you can do 2&3 in reverse if it makes more sense) big ones, then use TB to 'freeze' as many *SENSE* and *HTC* as you think you don't use (be careful or you'll have to restore a backup). If it's running OK with the things frozen, then you can return to the file system (./system/app) and delete the ones you've frozen. You can tell from TB which filenames go with which apps you've frozen.

4) Delete them or move them if it makes you feel safer to /sdcard/{create a dir here}.

5) df ; and look at free space in /system. It should be getting larger. When you've got ~20-30 free, you've got plenty for most things, and can remount /system a r/o (read-only).

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Why? For example: If you wanted to install, for some reason, one of Lou's kernels, where he for some reason, uses separate modules for everything (It is nice in desktop linux, but sucks in the droids), then they'll go into /system/lib/modules/* and eat up a ton of space (Like 25M), and basically fail on your current system.

If you use one of Ziggy's kernels, he tends to compile all modules but Wifi into the kernel itself, coming up with a similarly sized kernel as Lou but with the functionality built-in. I use all the functionality so I like that, but if you're using the stock kernel and don't care, then forget that.

HTC did some nutty stuff with this thing, like /emmc having 6+ GB but none of it is of much use to most users, then /data/data which is where all the userspace programs keep their data and libs, is tiny, giving way to the 'out of space' message when installing programs. Google Earth, for example uses 30M in libs itself.

The only reason I used the syntax *[sS][Ee]* etc, was because I fixed this up long enough ago so that I forgot if Sense and HTC apps were case sensitive (I mean used upper case and lower or some combo of those), so this is just covering bases.

If you don't use much social networking stuff (99% of HTC & Sense apps), then you don't need a lot of /system/app files and will do OK. If you use all of that, then I suppose you're stuck unless you can locate other things you never use. (there has to be stuff you don't use). If it gets deleted from /system/... then it releases space to you in what you're calling the system ROM.

Use caution -- Changing anything from /system is asking for trouble, so make sure it's not a showstopper.

Good luck - Hashi