Pixel 2 XL Testing, Celluar data Denied.

[atomos]

Testing steps:

1. Insert China Telecom(CHN-CT) sim card, edit APN settings as the same as Android system.
2. check the list of ISP, only List CHN-CT.
3. Celluar Searching for 3～5 minutes, show me Denied.

because Pixel 2 XL not fully supported China Telecom, in Android system I can modify Vendor partiton(copy .mbn files from other phone, edit oem_sw.txt).

so I just boot TWRP. the I can mount Vendor partiton and modify it. after this i do a factory reset in ubuntu touch os.
then do a new testing, but no miracle. phone app says "no service" and Celluar Denied.