7i43 with 7i48 and 7i34

Are you sure you have the correct 7I43 configuration and pinout for sserial on the 7I34?

What does

sudo mesaflash --device 7I43 --epp --addr 0x378 --program yourbitfile.bit
sudo mesaflash --device 7i43 --epp --addr 0x378 --readhmid

( with the 0x378 address and "yourbitfile.bit" changed to match your setup )

print?

post the printout here by running:

sudo mesaflash --device 7i43 --epp --addr 0x378 --readhmid > mypinout.txt

and posting mypinout.txt here

Ok, thanks.
I will try it in the next few days and i'll send you back the informations.