Hey, I thought I'd throw my hat into this since I got this working today, from scratch, on a Mitel 5330, with no prior knowledge about how mitel phones work (but plenty of polycom TFTP experience).
#1 - you don't need the sip5340ttnlang_en_US.bin
-- everything is already in english by default!
#2 - you DO need L2Boot53xxTtn8M.bin
#3 - you do NOT need MainIp5340.bin
#4 - you DO need the Minet
#5 - you DO need L2Boot_5340.bin
#6 - you DO need BootIp5340.bin
#7 - you MUST have a MN_Generic.cfg
#8 - you MUST have a MN_<MACADDR>.cfg file
#9 - you do not need sip5340ttntone_EN.bin
Your phone model in the MN_Generic.cfg file must match exactly -- 5330 vs 5330e is different and will not work!
When it does work, the phone will download a few firmware files, reboot, download similar ones and reboot again - this is the firmware upgrade and switch to the IP-based website.
When you surf to the phone's IP at first and it points you to the TFTP server, set it to English and point it at your TFTP server. Monitor the tftp daemon it to make sure it goes!
I lifted my configs right out of the previously posted .doc file, and I have them attached (and scrubbed).
Hope this helps!