Built-in Windows CE Driver - redirect to different driver version?

Two questions:
1-Is there a way to have a device use a driver other than the built-in driver that Windows CE provides?
1a-^Would renaming the driver/replacing the .dll in /Windows work?
1b-Would that dll be needed to be registered using regsvrce?

2-Is there anyway to locate the driver? Supposedly Windows CE 3.0 & 4.2 include a driver beginning in com_xxxxx.dll but it can't be located in /Windows

The driver in question is for 16550 Serial - Serial port driver for 16550 UART - supposedly it's called com16550.dll or com_card.dll

You would either have to add more specific pnp ID data to the registry for the new driver, or remove the pnp associations for the old driver from the registry.

Regsrving the new Dll is usually enough to add more specific ones, unless it is badly written or you are trying to hack hardware onto an unofficial driver.

As far as I know driver DLLs aren't regsrv'd, at least the telnet driver didn't have the right entrypoints

If they have a registration entry point, you don't get prompted for the driver name by CE because it registers the PnP ID in the registry automatically. The CAB installer can also be used to do the same though, which is often easier for the developer.

To be perfectly honest, and I’m sorry, but this goes over my head a little. I’m just not very experienced.
Anyway, I had some questions and ideas for how to accomplish this

1-we know that Windows CE 3.0 on the 900 does indeed work with the built in driver for the serial card (ce 4.2 does not, it crashes/hangs upon opening a com port)
2-would it be easier to see if we could switch that driver on ce 3.0 to the socket driver?
3-or just jump ahead and attempt to do that on ce4.2?

I was thinking of checking the registry six separate times if I knew where to look
1-ce3.0 hard reset no serial card installed
2-ce 3.0 with serial card installed , system default driver
3-ce 3.0 with serial card installed, socket driver
4-4.2 hard reset no serial card installed
5-ce4.2with serial card installed , system default driver
6-ce 4.2 with serial card installed, socket driver

What CE version is the DLL compiled for?

Do you mean which version the official driver for the Socket Serial I/O card was compiled for?
I assume Windows CE 3.0 based on the file name in the HCL
https://www.hpcfactor.com/downloads/details.asp?r={63EBB770-181E-4903-83AB-578234D4A5C6}
"output.HPC2000ARM.CAB"
How do I tell the version from the .dll it was compiled for? Or do you just literally mean to assume based on file names
^There's also WM2003/WM5 drivers as well for this card, but those didn't work either, if I recall correctly.

Well presumably the HPC2000 CAB is swapping the card to use the correct driver, surely? Else why would they release the driver

Am I misunderstanding something here?

Sorry, it's my fault, I didn't properly explain.
Basically:
The Socket Serial I/O CF Card works with the built in Windows CE drivers on Windows CE 3.0 for the MobilePro 900
but on Windows CE 4.2 the built in Windows CE drivers, it locks up the device when opening a COM port.
^and installing the HPC2000/WM2003 cabs don't seem to help, it does the same behavior

I was trying to figure out how to bypass that built in 4.2 driver and use either the HPC2000 driver provided by Socket in our HCL, or even the WM2003/WM5 driver dlls.
^I'm trying to get this card working in CE4.2

Some advanced setup instructions for Windows Mobile starting on p.6 I think

https://www.bb-elec.com/About-Us/Quatech/Quatech-Downloads/Older-Serial-IO-Cards/Older-Serial-IO-Cards/Serial-io-older-User-Guide.aspx