JFFS2: Maximum image size

building my own images, I encountered the problem that flashing a too large custom image caused the router to factory reset on reboot: jffs2: Too few erase blocks (5)
in the irc channel I learned that my firmware images may have a maximum size of 0x00e80000-0x50000 that is 0xe30000 - or 14876672 bytes.

I couldn't find clear information in this in the wiki. Maybe it would make sense to explain this in

I believe the explanation would be that for nor-flash/JFFS2 targets, the image size (wc -c image.bin) may not exceed the size of the firmware section in /proc/mtd minus five blocks used for jffs2 garbage collection totalling in x50000, that is 327680 bytes of overhead.

Is this correct?