Be warned, both RB1100AHx2 and RB1100AH (x1) have this small flash.
I've just bought a RB1100AH specifically because it had 512MB NAND flash according to the distributor (while they say the x2 has 64MB), compare:
http://cdr.pl/index.php?p1450,routerboa ... outeros-l6
http://cdr.pl/index.php?p1453,mikrotik- ... rb1100ahx2
And the RB1100AH (x1) supports Metarouter (didn't work initially, but I found on this forum how to fix it: upgrade to 5.14 then downgrade to 5.12 and upgrade to 5.14 again) so it could really use more flash for openwrt images. Any hope for using microSD for that?
And, it's a pity that the "flagship" 1100AHx2 can do less than the x1 - Metarouter, if supported, could make good use of the dual core CPU. Right now, the only good use for the x2 I can see is a BGP router (lots of RAM for the full routing tables).