Apparently the modded CPUMiner above only works for the USB single-chip version.
All the help and info that I found here and other forums always assume that we are using the controller that we don't have.
So I guess I'll wait for rescue from Beastlymac on this one

So is it not yet possible to run the 5-chip units under linux then? Does any linux miner software exist? I compiled the gridseed github minerd and got the same issues:
[2014-02-27 20:58:21] Stratum detected new block
[2014-02-27 20:58:21] dispatching new work to GC3355 LTC core
>>> LTC : 55aa1f2810000000
>>> LTC : 55aa1f2813000000
>>> LTC : 55aa1f00000000000000000000000000000000000000000000000000000000f8ff07000080bf3c3568ca9f531593a7b6dffa29244a573124dd9059e53303ba459ca468980000000138e115835fe6ad35d677b3447a2965f630064c61ac67a8f82eaddd534136520e681bdb830e38f3d393c2b4b7d667ebd66c1fbd29a2a65d7e3b4b19fc8c12525e530fa6f11c56ffb100000000ffffffff