Why my system hangs on startup
Reason: Socket Services driver is BASEDEV device and load early in OS/2 Boot process. At the driver load time OS/2 had no chance yet to built table of used resources. Therefore the OS/2 Socket Services driver may run in conflict with device drivers that are load later.
Solution: For CardBus you may run either into IRQ resource conflict or into memory resource conflict. First of all search IRQ. Please use any publicly available diagnostic software for check which IRQs are available on your system. Then add adapter and socket IRQ mask to SSPCIC.SYS command line. E.g. if you found that only IRQs 5, 7 and 10 are available, you should add to your command line following:

/MH:0xFB5F /FS:0xFB5F

Please notice, that you you plan to using LPT port for e.g. multi-function printer, you should also exclude IRQ 7.

Please also notice that OS/2 was written at the time when only one IDE adapter was commonly used. Therefore OS/2 considers IRQ 15 as available. On today PC however both IDE adapters are present and IRQ 15 is almost always in use. Therefore most likely you have to add at least /MH:0x8000 /FS:0x8000.

The second reason of conflict could be memory. The CardBus adapter requires 4kB memory window for map socket registers there. In order to access CardBus and ExCA registers of the socket adapter CardWare tries to allocated 4kB of memory for each socket. By default SSPCIC search any empty 4 KB of memory between 0x40000000 and 0x60000000 (i.e. 1GB and 1.5GB). If your computer has 1.5 GB of RAM or more you will need to shift this area to unused address space. You can change above limits via /RS and /RE parameters of SSPCIC. E.g. /RS:0x50000000 /RE:0xA0000000.