Uhm…
UPD: It seems, somehow I started rephone’s 6.4 vxp (while I still on old “firmware” (bootloader and so. I.e. I didn’t “flashed” anything, only playing with mass storage mode, since I can’t see a way for firmware upgrading on non-windows hosts)), and it creates ttyACM{0,1} files too (as lua), when started.
And… there are all the same in ACM-ports: nothing in ACM0 (looks like it is modem port, while it answers on AT-commands, so I was mistaken in OP) and tons of binary crap in ACM1 (which should be debug port then, I assume).
So, I mostly discouraged with the fact that PuTTY on the RePhone’s wiki shows lua command prompt with only single setting changed (assuming CR on LF), while I see tons of crap there in both PuTTY an minicom (maybe there is some another recommended software for unixlike hosts?).