So you're looking at 8 MB of which, after firmware, you have roughly 4 MB available -- and that number is perfectly reasonable. Also, while it's not "a lot", it's also not "very little." A selection of all but the very expansive packages should fit fine, especially since you can't make huge leaps with 64 MB of RAM either.
If you don't intend to run a web and database server or a torrenting box, you should be fine. Like I amended above, you will probably hit the RAM limit earlier than the flash limit.
If you do run into space problems, building packages into the ROM with either the image builder or from source compresses them by around a factor of two.
I agree that RAM is likely a concern running anything "big".
not a webserver
I wanted to add bluetooth BLE support (usb dongle) (~1MB) and a python (1.5MB) + a few libs to run script that handle a sensor.
my ram is currently 61% full (idle, 2 stations connected on wifi).
I wanted to use this device because it's close to the sensor, but maybe it's not a good choice...
(@takimata...greetings from France my router is Japanese, but I'm not, got it from ebay )
Yes, exactly that. Don't be afraid, using the imagebuilder is easier than you think.
And it's worth the effort, since you will "gain" precious flash space compared to installing via opkg.
You are likely to have RAM exhaustion problems as well as not being able to fit it on even a 16 MB device (with an Archer C7v2 and 16 MB of flash, I could not get a "reasonable" Python install to fit).
Guys, I base all this discussion thinking about plugging a USB bluetooth dongle on the router.
In my mind, there was a usb port on it...but while trying to plug the dongle....Well....there is no USB on this device (so stupid from me...)
Anyway, I learned several things here about memory! I think I will keep this device as dumb ap for the moment and consider a different one for my bluetooth playing...(with USB port!!! and with much better knowledge about RAM/flash size to consider)