[Nexus 7 Q&A, Help & Troubleshooting] bftb0:
Sorry k91191 for not getting back to this thread. I don't use e-mail notifications, so I slipped up on this one.

I just booted my grouper two times - once using TWRP 2.6.3.1 and once using a CyanogenMod 10.2 kernel (a nightly from 9/22). Here are the mmc- related kernel messages:

TWRP kernel (TWRP 2.6..3.1)

<4>[ 5.715260] mmc0: Invalid maximum block size, assuming 512 bytes
<7>[ 5.716525] Registered led device: mmc0::
<6>[ 5.719914] mmc0: SDHCI controller on sdhci-tegra.3 [sdhci-tegra.3] using ADMA
<4>[ 5.721257] mmc1: Invalid maximum block size, assuming 512 bytes
<7>[ 5.722463] Registered led device: mmc1::
<6>[ 5.724691] mmc1: SDHCI controller on sdhci-tegra.2 [sdhci-tegra.2] using ADMA
<6>[ 5.797969] [mmc]:mmc_decode_cid:113 cid.prv 0x1
<6>[ 5.809412] [mmc]:mmc_read_ext_csd:285 ext_csd.sectors 0x3b78000 prod_name MMC32G BOOT_MULTI 0x10
[b]<6>[ 5.811368] mmc0: new high speed DDR MMC card at address 0001
<6>[ 5.811573] mmcblk mmc0:0001: Card claimed for testing.
<6>[ 5.811942] mmcblk0: mmc0:0001 MMC32G 29.7 GiB
<6>[ 5.812175] mmcblk0boot0: mmc0:0001 MMC32G partition 1 2.00 MiB
<6>[ 5.812467] mmcblk0boot1: mmc0:0001 MMC32G partition 2 2.00 MiB
[color=green]<6>[ 5.814738] mmcblk0: p1 p2 p3 p4 p5 p6 p7 p8 p9[/color]
<6>[ 5.816718] mmcblk0boot1: unknown partition table
<6>[ 5.817971] mmcblk0boot0: unknown partition table[/b]
<6>[ 5.818225] [mmc]:mmc_rescan_try_freq:1907 mmc0: eMMC completed

CyanogenMod kernel (20130922-Nightly)

<4>[ 3.493854] mmc0: Invalid maximum block size, assuming 512 bytes
<7>[ 3.495082] Registered led device: mmc0::
<6>[ 3.498527] mmc0: SDHCI controller on sdhci-tegra.3 [sdhci-tegra.3] using ADMA
<4>[ 3.499809] mmc1: Invalid maximum block size, assuming 512 bytes
<7>[ 3.501001] Registered led device: mmc1::
<6>[ 3.503290] mmc1: SDHCI controller on sdhci-tegra.2 [sdhci-tegra.2] using ADMA
<6>[ 3.578428] [mmc]:mmc_decode_cid:113 cid.prv 0x1
<6>[ 3.589857] [mmc]:mmc_read_ext_csd:285 ext_csd.sectors 0x3b78000 prod_name MMC32G BOOT_MULTI 0x10
[b]<6>[ 3.591774] mmc0: new high speed DDR MMC card at address 0001
<6>[ 3.592051] mmcblk mmc0:0001: Card claimed for testing.
<6>[ 3.592365] mmcblk0: mmc0:0001 MMC32G 29.7 GiB
<6>[ 3.592659] mmcblk0boot0: mmc0:0001 MMC32G partition 1 2.00 MiB
<6>[ 3.592886] mmcblk0boot1: mmc0:0001 MMC32G partition 2 2.00 MiB
[color=green]<6>[ 3.595089] mmcblk0: p1 p2 p3 p4 p5 p6 p7 p8 p9[/color]
<6>[ 3.597134] mmcblk0boot1: unknown partition table
<6>[ 3.598279] mmcblk0boot0: unknown partition table[/b]
<6>[ 3.598530] [mmc]:mmc_rescan_try_freq:1907 mmc0: eMMC completed

... and now here is your kernel boot messages:

<4>[ 3.426851] mmc0: Invalid maximum block size, assuming 512 bytes
<7>[ 3.428115] Registered led device: mmc0::
<6>[ 3.431508] mmc0: SDHCI controller on sdhci-tegra.3 [sdhci-tegra.3] using ADMA
<4>[ 3.432789] mmc1: Invalid maximum block size, assuming 512 bytes
<7>[ 3.434026] Registered led device: mmc1::
<6>[ 3.436234] mmc1: SDHCI controller on sdhci-tegra.2 [sdhci-tegra.2] using ADMA
<6>[ 3.531173] [mmc]:mmc_decode_cid:113 cid.prv 0x1
<6>[ 3.542706] [mmc]:mmc_read_ext_csd:285 ext_csd.sectors 0x3a40000 prod_name HBG4e BOOT_MULTI 0x10
[b]<6>[ 3.548773] mmc0: new high speed DDR MMC card at address 0001
<6>[ 3.548962] mmcblk mmc0:0001: Card claimed for testing.
<6>[ 3.549328] mmcblk0: mmc0:0001 HBG4e 29.1 GiB
<6>[ 3.549602] mmcblk0boot0: mmc0:0001 HBG4e partition 1 2.00 MiB
<6>[ 3.549887] mmcblk0boot1: mmc0:0001 HBG4e partition 2 2.00 MiB
[color=red]<6>[ 3.552271] mmcblk0: unknown partition table[/color]
<6>[ 3.557636] mmcblk0boot1: unknown partition table
<6>[ 3.560092] mmcblk0boot0: unknown partition table[/b]
<6>[ 3.560341] [mmc]:mmc_rescan_try_freq:1907 mmc0: eMMC completed

I wouldn't be very optimistic. That seems to suggest that your kernel can not detect ANY valid android partitions.

I note that you seem to have a eMMC Flash Memory chip from a different vendor than I (HBG4e vs. MMC32G). I doubt that is relevant, though.

I am not aware of a single report here in the N7 forums where someone actually altered or restored the eMMC partitioning.

I'm sure it can be done - but only by Asus (perhaps with an engineering bootloader, or using nvflash with knowledge of the security keys).

sorry.