6i24-25 and 7i52S

I dont think there is a 5I24-25 project file so you need to change
the FPGA chip in the project properties

( select top level file in file pane, right click and select "design properties" )

Yes find
device XC6SLX16 to device XC6SLX25 (not device XC6SLX25T) ?

Yes, change to XC6SLX25-FTG256
Also make sure the speed is 2. Some versions of ISE set the speed to 3 when you change the chip type so you need to change the type, close the properties pane, reopen the properties pane and change the speed.

Perfect, thank you PCW, (and talla83 ...)

the card is flashed and with "readmid", all the inputs/outputs are good.

I also have a 6i24 card connected to a 7i52S. I tried the linked firmware file, but it appears to not be loading into my 6i24 card; linuxcnc reports finding a 5i24 card (33 MHz PCI clock, so that makes sense), but then reports all 72 I/O pins as being GPIOs. No encoder lines or step generator pins. Am I missing something, or do I have a different 6i24 that isn't supported by the firmware file? How would I check the model of 6i24? Thanks for any help.

6I24s are normally setup to emulate a 5I24 and use 5I24 bit files

LinuxCNC cannot load the FPGA on cards with flash memory like the 5I24/6I24,
you must use the mesaflash utility and program the card with a
5I24_25_xxxx.bit or 5I24_16_xxxx.bitfile depending on the 6I24 card model.