I've mentioned it before, so just a reminder - using both eMMC swap and microSd swap *at the same time* is pointless, as performance gain is only theoretical. Google for "usb flash raid" or "pendrive raid" to have some fun reading, about why so

In N900 case, it's even worse, as swapping on eMMC create I/O conflicts with writes to /home and /opt (which is in eMMC, too). Flash isn't best at handling simultaneous writes to different partitions on same physical device. Result is, that having *both* eMMC flash and microSD flash active - no matter if with same priority, or microSD with higher priority - results in considerable performance drop, and possibility of watchdog reboots on heavy I/O load.

/Estel

// Edit

Yea, it's just about using both main and backup swap on microSD. No swap on eMMC at all.

One workaround is to move swap into eMMC, temporally, then, remove backcover, and move it back into microSd after putting backcover back. It can be accomplished by some shell scripts (that would handle safely unmounting vfat on microSD, too).

Hoever, there is another method, prefered by me - glue'ing small magnet in approriate place of N900 body, where sensor is located. It's trivial, doesn't even require disassembling on N900, and works like charm - it's "do it and forget" solution. I'm using it for a loooong time, and never encountered any problems, + I can remove backcover whenever I want.

Of course, it would be very, very bad, if You would be stupid enough to remove microSD card from slot, without disabling swap on it and unmounting it (although, what Maemo does, when You remove backcover, is almost the same) - but, we assume some sanity of user

/Estel

// edit 2

Best source of small magnet is cheap pair of earpiece headphones, small ones, even the 0.50$ Chinese type. After tearing it apart, You will see small neodymium magnet - best one. you can cut it freely, getting very small part, that won't cause problems with attaching backcover. Just glue it with good glue, and You're good to go.