[Android Q&A, Help & Troubleshooting] fixerdave:
I'm looking for some experienced eyes to scan through the partition info of a CyberNav tablet that I've mucked up by being very stupid. The CyberNav is a cheap Chinese GPS/Android tablet. It works great, or rather worked great until I very stupidly left it attached to my computer after downloading a track of my latest dirtbiking exploits. Later that evening I decided to make another Ubuntu USB startup disk... well, you can guess the rest.

At this point, the tablet will not mount the internal "sdcard" memory. It still boots, everything works, not bricked yet. When connected to USB, it will share out this external storage just fine. It just won't mount it within Android. It reports "Preparing memory device, checking for errors." Never gets past that point. I do have a backup of the original internal sdcard contents (made that when I first got the device) and anything that was important to me. Yes, I make backups, been burned too many times. I've also managed to find a factory ROM for it and I've successfully flashed that to the device. It made no difference with the problem. I've also got a root prompt via ADB shell using psneuter.

I have a copy of parted and gdisk, though I've not tried to run them yet. In other words, it's time to start figuring out what to fix in the partition tables.

I think the problem is here:

# busybox fdisk -l /dev/block/mmcblk2p6

... Device Boot Start End Blocks Id System

/dev/block/mmcblk2p6p1 1 1017 3436381 5 Extended <<<<< HERE

/dev/block/mmcblk2p6p5 1 1017 3436379 b Win95 FAT32

Does that seem right? Am I in any danger of bricking this device if I blow away the mmcblk2p6p1 partition and/or the entire mmcblk2p6? How bad do things generally have to get in these partitions before the device bricks?

What is the best/safest way to remove this partition and if I have to blow the whole mmcblk2p6 partition away will I have to manually recreate it before rebooting?

Any advice appreciated,

David...

P.S. Here is all the hopefully relevant information I've so far managed to locate:

Cybernav Mini: CPU: IMAPX200 ARM11 800MHz, also known as YFPi08, now flashed to Android 2.2-104.

# cat /proc/partitions

major minor #blocks name
179 16 3878912 mmcblk2
179 17 4096 mmcblk2p1
179 18 8192 mmcblk2p2
179 19 153600 mmcblk2p3
179 20 1 mmcblk2p4
179 21 277760 mmcblk2p5
179 22 3435072 mmcblk2p6

# busybox fdisk -l /dev/block/mmcblk2

Disk /dev/block/mmcblk2: 3972 MB, 3972005888 bytes
1 heads, 16 sectors/track, 484864 cylinders
Units = cylinders of 16 * 512 = 8192 bytes

Device Boot Start End Blocks Id System
/dev/block/mmcblk2p1 9 520 4096 30 Unknown
Partition 1 does not end on cylinder boundary
/dev/block/mmcblk2p2 521 1544 8192 31 Unknown
Partition 2 does not end on cylinder boundary
/dev/block/mmcblk2p3 1545 20744 153600 83 Linux
Partition 3 does not end on cylinder boundary
/dev/block/mmcblk2p4 20745 484864 3712960 5 Extended
Partition 4 does not end on cylinder boundary
/dev/block/mmcblk2p5 20753 55472 277760 83 Linux
/dev/block/mmcblk2p6 55481 484864 3435072 b Win95 FAT32

# busybox fdisk -l /dev/block/mmcblk2p6

Disk /dev/block/mmcblk2p6: 3517 MB, 3517513728 bytes
109 heads, 62 sectors/track, 1016 cylinders
Units = cylinders of 6758 * 512 = 3460096 bytes

Device Boot Start End Blocks Id System
/dev/block/mmcblk2p6p1 1 1017 3436381 5 Extended
/dev/block/mmcblk2p6p5 1 1017 3436379 b Win95 FAT32

# cat /proc/kmsg

...
<3>[ 2.295000] imapx200_iic imapx200_iic.0: iic thread TX_ABORT occur
<3>[ 2.295000] imapx200_iic imapx200_iic.0: source is 1
<3>[ 2.295000] imapx200_iic imapx200_iic.0: slave address is 1a
<4>[ 2.300000] mmc_request bus 2 cmd 5 error -110
<4>[ 2.300000] mmc_request bus 2 cmd 5 error -110
<4>[ 2.300000] set info,open device error -939392608
<4>[ 2.305000] mmc_request bus 2 cmd 5 error -110
<3>[ 2.305000] imapx200_iic imapx200_iic.0: iic thread TX_ABORT occur
<3>[ 2.305000] imapx200_iic imapx200_iic.0: source is 1
<3>[ 2.305000] imapx200_iic imapx200_iic.0: slave address is 1a
<4>[ 2.305000] mmc_request bus 2 cmd 5 error -110
<6>[ 2.330000] mmc2: new high speed SDHC card at address 0002
<6>[ 2.330000] mmcblk2: mmc2:0002 3.69 GiB
<6>[ 2.335000] mmcblk2: p1 p2 p3 p4 < p5 p6 >
<4>[ 2.400000] custom info start sector 8182
<4>[ 2.430000] i2c-imapx200 transfer timeout
...
<6>[ 4.095000] EXT4-fs (mmcblk2p3): mounted filesystem with ordered data mode
<6>[ 4.635000] EXT4-fs (mmcblk2p5): recovery complete
<6>[ 4.645000] EXT4-fs (mmcblk2p5): mounted filesystem with ordered data mode
...
<3>[ 26.285000] FAT: invalid media value (0xa5)
<6>[ 26.285000] VFS: Can't find a valid FAT filesystem on dev mmcblk2p6.
... x3 above spaced to end of log.

dmesg:

...
<6>[ 0.295000] Imap Framebuffer Driver Initialization OK!
<4>[ 0.340000] set info,open device error -939392608
<4>[ 0.440000] set info,open device error -939392608
<4>[ 0.540000] set info,open device error -939392608
<4>[ 0.640000] set info,open device error -939392608
<4>[ 0.740000] set info,open device error -939392608
<4>[ 0.845000] set info,open device error -939392608
<6>[ 0.925000] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
...
<3>[ 96.180000] FAT: invalid media value (0xa5)
<6>[ 96.180000] VFS: Can't find a valid FAT filesystem on dev mmcblk2p6.
... x2 above