error: failed to read cfg item 3703: Input/Output Error about cp210x-cfg HOT 2 OPEN

I forked the project and added support for the newer cp2102n chips
https://github.com/irrwisch1/cp210x-cfg

from cp210x-cfg.

i tried set serial on linkit 7697 which has cp2102n.
further investigation led to
https://www.silabs.com/documents/public/application-notes/AN978-cp210x-usb-to-uart-api-specification.pdf
and https://www.silabs.com/documents/public/application-notes/an976-cp2102-3-4-9-to-cp2102n-porting-guide.pdf and https://www.silabs.com/documents/public/application-notes/AN721.pdf

AN978 satements:
CP210x_SetConfig() Programs the entire configuration of a CP2102N device.
CP210x_GetConfig() Gets the entire configuration of a CP2102N device as a byte array.
CP210x_GetXXXXXXX() calls usually works also on CP2102N, but some only on non-N versions.

also contains full description of CP2102N configuration array.

btw it would be worth to poke at https://github.com/remakeelectric/cp210xmanufacturing

from cp210x-cfg.