This seems to be an official dev board. It’s available from taobao for ~$200.
The vendor provided a copy of the SDK but no schematics or chip documentation.
Bus 002 Device 006: ID 1b20:8888
Bus 001 Device 001: ID 1d6b:0002
Bus 002 Device 001: ID 1d6b:0002
LPLL
/ # devmem 0x1f206700
0x00002201
/ # devmem 0x1f206704
0x00000420
/ # devmem 0x1f206708
0x00000042
/ # devmem 0x1f20670c
0x00000001
/ # devmem 0x1f206710
0x00000000
/ # devmem 0x1f206714
0x00000000
/ # devmem 0x1f206718
0x00000000
/ # devmem 0x1f20671c
0x00000000
/ # devmem 0x1f206720
0x0000C3C3
/ # devmem 0x1f206724
0x00000043
/ # devmem 0x1f206728
0x00000001
/ # devmem 0x1f20672c
0x00000000
0x000000140000-0x0000001a0000 : "IPL0"
0x0000001a0000-0x000000200000 : "IPL1"
0x000000200000-0x000000260000 : "IPL_CUST0"
0x000000260000-0x0000002c0000 : "IPL_CUST1"
0x0000002c0000-0x000000380000 : "UBOOT0"
0x000000380000-0x000000440000 : "UBOOT1"
0x000000440000-0x0000004a0000 : "ENV0"
0x0000004a0000-0x0000004c0000 : "KEY_CUST"
0x0000004c0000-0x000000520000 : "LOGO"
0x000000520000-0x000000a20000 : "KERNEL"
0x000000a20000-0x000000f20000 : "RECOVERY"
0x000000f20000-0x000008000000 : "UBI"