Hi, first post here. I was looking for the rs232 connection on my newly bought NBD8008R - 3536DV100 V1.01 Hangzhou Xiongmai First I was looking at the 4 pin connector CN4, but that seems to be a USB host. I finally found some chinese description online It wasn't quite the same board, but atleast I knew now I had to look close to the CN3 connector. There were 4 solder islands close together CN8, so soldered some pins on there and tried.... Success. I also needed to set the RS232 in the interface to InteractCmd. I used minicom on my linux machine to output the boot. Code: System startup.......... System startup U-Boot 2010.06-svn1060 (May 14 2018 - 15:54:41) Check Flash Memory Controller v100 ... Found SPI Nor(cs 0) ID: 0xc2 0x20 0x18 Block:64KB Chip:16MB Name:"MX25L128XX" CONFIG_CLOSE_SPI_8PIN_4IO = y. at hifmc100_setTB() mid:0xc2,chipsize:0x1000000 <no>. lk[8 => 0x800000] SPI Nor total size: 16MB In: serial Out: serial Err: serial USB: scanning bus for devices... 2 USB Device(s) found 0 Storage Device(s) found i:0, No usb storage device found! Press CTRL-C to abort autoboot in 2 seconds16384 KiB hi_fmc at 0:0 is now current device CFG_BOOT_ADDR:0x0 argc 2 argv logoload ### h264dvr.jpg UbootLogoload complete:bytes oadaddr0x84000000 loaded to 0x87000000 ### h264dvr.jpg UbootLogoload complete: 59577 bytes loaded to 0x87000000 jpeg decoding ... <<addr=0x87000000, size=0xb85f9, vobuf=0x8711fc00>> <<imgwidth=800, imgheight=600, linebytes=1600>> decode success!!!! decode jpeg success. decode jpeg! stMaxRect.u32Width:800, stMaxRect.u32Height:600. HDMI_INFO:DispFmt2HdmiTiming ,Non CEA video timing:16 HDMI_INFO:Hdmi_PixelFreqSearch ,u32Fmt16. srcAddr 0x82000000, dstAddr 0x81000000 find_squashfs_file: name bin, start_block 0, offset 2608, type 1 find_squashfs_file: name boot, start_block 0, offset 2716, type 1 read inode: name boot, sb 0, of 2716, type 1 find_squashfs_file: name zImage.img, start_block 0, offset 2640, type 2 read inode: name zImage.img, sb 0, of 2640, type 2 ### FS load complete: 2824707 bytes loaded to 0x81000000 ## Booting kernel from Legacy Image at 81000000 ... Image Name: Linux-4.9.37 Image Type: ARM Linux Kernel Image (uncompressed) Data Size: 2824643 Bytes = 2.7 MiB Load Address: 80008000 Entry Point: 80008000 Loading Kernel Image ... OK OK Starting kernel ... My final goal is to add some ftp server or smb server, so I can access my recordings easily. Since I am not a windows user and almost all available tools like activeX, CMS are only on windows available.