The /dev/mmcblk1boot0 and boot1 devices are special locations where (if the hardware supports them) you can install u-boot separate from a normal MBR filesystem on the /dev/mmcblk1 device, but GXBB (and GXL/GXM) do not support this. The first Amlogic devices that do suppport it are G12A (S905X2/D2/Y2).
The non-standard location is simply an offset (shifted X sectors). However this is only visible-to and understood by Amlogic u-boot which has the internal juju to understand the offset and it's own partition tools. All normal userspace apps like fdisk/parted cannot see the partitions that have been created. You can see this when booting the LE10 WP2 image on a factory state box and running "emmctool i" - it can see the emmc device but no filesystems are listed on it.
If you want the DVB tuners to work you will need to restore to an LE9 or CE9 image as there is currently zero support for the DVB cards used in Amlogic boxes in the mainline kernel. This also solves the SD card issue as the device will boot from eMMC. This image will restore the box to WeTek/Android state Dropbox - backup-wp2.img.gz - Simplify your life .. then boot from SD card (the LE10 WP2 image) and use emmctool or dd to write the file to emmc. USB should also work as an alernative to SD .. I've done it numerous times with other boxes but can't say I've ever bothered with a WP2 as mine has a working SD slot. YMMV.