[Samsung Galaxy Nexus] xdsme:
Hello, guys!

This morning I found my phone with black screen and not responding to power button. I pulled the battery out and tried to boot. The phone only showed the "Google" text on the black screen for several minutes (five, may be ten minutes) and did not respond to any buttons. At this point I pulled the battery for the second time and tried the recovery mode. The stock recovery booted after about a minute of "Google" screen. In stock recovery the only option I tried first time was "Wipe cache". It showed a static image of "work-in-progress" with static progress bar for several seconds and then returned to main recovery screen. I tried the "reboot" and received the black screen with no buttons working.

Pulled the battery and tried normal boot, which stuck on black "Google" stage.

Ok, I connected the phone to my laptop, and booted TWRP via fastboot, it took a little longer to boot, but at least I managed to "adb-shell" it and grab dmesg output. This is the relevant part (containing "mmc" word):

<6>[ 2.828399] mmc0: new high speed MMC card at address 0001
...
<6>[ 2.829101] mmcblk0: mmc0:0001 VYL00M 14.6 GiB
<6>[ 2.829345] mmcblk0boot0: mmc0:0001 VYL00M partition 1 512 KiB
<6>[ 2.829681] mmcblk0boot1: mmc0:0001 VYL00M partition 2 512 KiB
<6>[ 2.835021] Reprogramming LPDDR2 timings to 400000000 Hz
<3>[ 2.836090] Power Management for TI OMAP4.
<6>[ 2.836334] OMAP4 PM: Static dependency added between MPUSS and DUCATI <-> L4_PER/CFG and L3_1.
<6>[ 2.836517] mmcblk0: p1 p2 p3 p4 p5 p6 p7 p8 p9 p10 p11 p12 p13
<4>[ 2.837432] sr_init: No PMIC hook to init smartreflex
<6>[ 2.837799] smartreflex smartreflex.0: omap_sr_probe: SmartReflex driver initialized
<6>[ 2.838073] smartreflex smartreflex.1: omap_sr_probe: SmartReflex driver initialized
<6>[ 2.838317] smartreflex smartreflex.2: omap_sr_probe: SmartReflex driver initialized
<6>[ 2.838592] sr_class1p5_driver_init: OMAP4460: add 10mV margin for class 1.5
<6>[ 2.838928] SmartReflex class 1.5 driver: initialized (86400000ms)
<6>[ 2.839569] mmcblk0boot1: unknown partition table
<6>[ 2.840728] [MODEM_IF] PA EVENT : reset =0, pa=1
<6>[ 2.840972] mmcblk0boot0: unknown partition table
...
<4>[ 3.851135] mmc1: queuing unknown CIS tuple 0x80 (7 bytes)
<4>[ 3.899353] mmc1: queuing unknown CIS tuple 0x80 (3 bytes)
<6>[ 3.915679] mmc1: new high speed SDIO card at address 0001
<4>[ 3.917633] F1 signature read @0x18000000=0x16844330
<4>[ 3.927154] DHD: dongle ram size is set to 294912(orig 294912)
...
<3>[ 7.677093] mmcblk0: timed out sending r/w cmd command, card status 0xe00
<3>[ 7.677276] mmcblk0: not retrying timeout
<3>[ 7.677581] end_request: I/O error, dev mmcblk0, sector 1495040
<3>[ 7.677764] Buffer I/O error on device mmcblk0p11, logical block 0
<4>[ 7.678100] lost page write due to I/O error on mmcblk0p11
<6>[ 7.678802] EXT4-fs (mmcblk0p11): recovery complete
<6>[ 7.679138] EXT4-fs (mmcblk0p11): mounted filesystem with ordered data mode. Opts: (null)
<3>[ 8.737213] mmcblk0: timed out sending r/w cmd command, card status 0x400e00
<3>[ 8.737304] mmcblk0: command error, retrying timeout
<3>[ 8.737426] mmcblk0: timed out sending r/w cmd command, card status 0x400e00
<3>[ 8.737548] mmcblk0: command error, retrying timeout
<3>[ 8.737701] mmcblk0: timed out sending r/w cmd command, card status 0x400e00
<3>[ 8.737762] mmcblk0: command error, retrying timeout
<3>[ 8.737915] mmcblk0: timed out sending r/w cmd command, card status 0x400e00
...

and a lot of I/O errors with mmcblk0 block device

Reading from /dev/block/mmcblk0 constantly fails, even the first sectors (dd if=/dev/block/mmcblk0 of=/dev/null).

I pulled the battery out, left the phone and rushed to the work.

With my little knowledge it looks like broken sdcard itself or sdcard controller. Does it make any sense? Is it possible to repair it easily? I realize I cannot simply replace sdcard, as it most likely soldered in the board, but how hard is it to replace if I have the equipment and spare parts?

Another question: as I can boot TWRP recovery via fastboot, is it theoretically possible to find and boot a custom kernel, which does not require internal storage at all, like some stripped kernel which works only in RAM, but still provides the basic functions like phone calling, wifi browsing and something like this?

Any help would be greatly appreciated!