I just picked up an Insignia Flex Elite 7.85", 2048x1536 with a RK3288 running 5.0.1 for $150 US. Looking at logcat when I turn on Bluetooth it looks like it has a Broadcom BCM4350 with WiFi A/B/G/N/AC. HW wise it is pretty good. AnTuTu 38005, plays HEVC up to 4K flawlessly. The firmware sucks. Can't see the SDcard in installed apps, only the factory file explorer. The adaptive brightness has one setting, really bright and drain the battery. It needs a root and a good ROM. Any idea if source code for 5.0.1/5.1.1 is available for something close enough I can hack?

It looks like LP is starting to come out for the RK3288!

You can see the photos, test reports and manuals on the FCC site here:

https://apps.fcc.gov/oetcf/eas/reports/ViewExhibitReport.cfm?mode=Exhibits&RequestTimeout=500&calledFromFrame=N&application_id=DJl9hP9UigO4iiKOURlE7g%3D%3D&fcc_id=XMF-MID7802

The Best Buy site listing is here: http://www.bestbuy.com/site/insignia-flex-elite-7-85-16gb-white-silver/5704046.p?id=1219659968086&skuId=5704046

I was unable to root and dump the firmware with your utilities, adb devices reports offline. With the 4.1 Release_DriverAssitant, adb doesn't have root access and can't chmod anything. I was able to get the images with the v2.33 AndroidTool. It is interesting that the VID when Android is running is 0x19FF and you need to add it to the adb_usb.ini to connect with adb. When in the bootloader or sideloader it is 0x2207 and you have to install the drivers for each mode from windows device manager. Please let me know where you would like me to post them. Here is the parameters text for now.

MANUFACTURER:RK3288
MAGIC: 0x5041524B
ATAG: 0x60000800
MACHINE: 3288
CHECK_MASK: 0x80
PWR_HLD:0,7,A,4,2
PWR_HLD: 0,0,A,0,1
#KERNEL_IMG: 0x62008000
#FDT_NAME: rk-kernel.dtb
#RECOVER_KEY: 1,1,0,20,0
CMDLINE:console=ttyFIQ0 androidboot.baseband=N/A androidboot.hardware=rk30board androidboot.console=ttyFIQ0 init=/init initrd=0x62000000,0x00800000 mtdparts=rk29xxnand:0x00002000@0x00002000(uboot),0x00002000@0x00004000(misc),0x00008000@0x00006000(resource),0x00008000@0x0000e000(kernel),0x00010000@0x00016000(boot),0x00010000@0x00026000(recovery),0x0001a000@0x00036000(backup),0x00200000@0x00050000(cache),0x00002000@0x00250000(kpanic),0x00300000@0x00252000(system),0x00008000@0x00552000(metadata),0x00020000@0x0055A000(radical_update),-@0x0057A000(userdata)
# in section; per section 512(0x200) bytes
#CMDLINE:console=ttyFIQ0 androidboot.baseband=N/A androidboot.selinux=permissive androidboot.hardware=rk30board androidboot.console=ttyFIQ0 init=/i

Here are the images you have listed in your batch file except the system. It is too big to attach at 540MB.