Bg95 ftpput LOCKS UP with upload chunk >~3800 bytes

IoT Modules LPWA Module
1

Using a BG95

BG95M3LAR02A03

BG95M3LAR02A03_A0.301.A0.301

While uploading files via ftps from COM source to a server :

I find 2 issues:

  1. Flow control set to 2,2.
    1. AT+IFC?
    2. Reply:
    3. +IFC: 2,2<\r>
  2. With upload chunks of 3800 bytes it uploads fine.
  3. With upload chunks of some size > this ( 4096 normally fails):
    1. It may upload a small number of chunks then lock up requiring reset / reboot.
    2. It may raise CTS line then never lower CTS line.
  4. With a previous firmware version in a different module, 4096 was safe, anything larger failed by dropping upload data. That was with no flow control.

I see no documentation as to allowable buffer size. Is there a published or limit that can be queried?

It also seems that the flow control in this is NOT functional for ftps.

Can any of this be verified??

Thanks