[Transformer TF300T Q&A, Help & Troubleshooting] XeL64:
Hi !

Got the same, flash with JB one on 4.2.1...

But, to load android : Power on (nothing else, automatic boot on twrp which adb works) => adb reboot-bootloader, on fastboot menu keep android and let's go Android 4.2.1 start well !

Now i try to root under android to get

for information you can mount some sdcard under twrp just mkdir /tmp/something and check fdisk -l /dev/block/* to found the sdcard (only try with sdcard on keyboard) mount /dev/block/<sda1 for example> /tmp/something.

I'll bring back dmesg log (from twrp) :

....

<4>[ 0.000000] Lowering sbc1 maximum rate from 160000000 to 100000000

<4>[ 0.000000] Lowering sbc2 maximum rate from 160000000 to 100000000

<4>[ 0.000000] Lowering sbc3 maximum rate from 160000000 to 100000000

<4>[ 0.000000] Lowering sbc4 maximum rate from 160000000 to 100000000

<4>[ 0.000000] Lowering sbc5 maximum rate from 160000000 to 100000000

<4>[ 0.000000] Lowering sbc6 maximum rate from 160000000 to 100000000

.....

<4>[ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 254468

<5>[ 0.000000] Kernel command line: tegra_wdt.heartbeat=30 tegraid=30.1.3.0.0 mem=1022M@2048M commchip_id=0 androidboot.serialno=015d14588717f[ 0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)

413 androidboot.commchip_id=0 video=tegrafb no_console_suspend=1 console=ttyS0,115200n8 debug_uartport=lsport,0 usbcore.old_scheme_first=1 lp0_ve[ 0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)

c=8192@0xbddf9000 tegra_fbmem=8197120@0xabc01000 core_edp_mv=0 audio_codec=wm8903 board_info=245:0:1c:a7:29 tegraboot=sdmmc gpt gpt_sector=620789[ 0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)

75 modem_id=0 android.kerneltype=recovery androidboot.productid=0x02 androidboot.carrier=wifi-only

<6>[ 0.000000] PID hash table entries: 4096 (order: 2, 16384 bytes)

<6>[ 0.000000] Dentry cache hash table entries: 131072 (order: 7, 524288 bytes)

<6>[ 0.000000] Inode-cache hash table entries: 65536 (order: 6, 262144 bytes)

.....

<6>[ 5.067672] sdhci: Secure Digital Host Controller Interface driver

<6>[ 5.067799] sdhci: Copyright(c) Pierre Ossman

<6>[ 5.067867] sdhci-pltfm: SDHCI platform and OF driver helper

<6>[ 5.068057] [mmc]:sdhci_tegra_probe:1161 mmc0: built_in 1

<6>[ 5.069028] sdhci-tegra sdhci-tegra.3: Error: tegra3 io dpd not supported for sdhci-tegra.3

<4>[ 5.070189] mmc0: Invalid maximum block size, assuming 512 bytes

<6>[ 5.070341] mmc0: no vmmc regulator found

<6>[ 5.073588] [mmc]:mmc_detect_change:1587 mmc0: gpio_69:0

<6>[ 5.073665] [mmc]:mmc_schedule_delayed_work:87 mmc0: delay 0

<6>[ 5.073812] [mmc]:mmc_rescan:2083 mmc0: gpio_69:0 rescan_disable 0

<6>[ 5.074985] mmc0: SDHCI controller on sdhci-tegra.3 [sdhci-tegra.3] using ADMA

<4>[ 5.075141] mmc1: enable Wi-Fi wake event

<6>[ 5.075241] sdhci-tegra sdhci-tegra.2: Error: tegra3 io dpd not supported for sdhci-tegra.2

<4>[ 5.076383] mmc1: Invalid maximum block size, assuming 512 bytes

<6>[ 5.076527] mmc1: no vmmc regulator found

<6>[ 5.079737] [mmc]:mmc_detect_change:1587 mmc1: gpio_69:0

<6>[ 5.079866] [mmc]:mmc_schedule_delayed_work:87 mmc1: delay 0

<6>[ 5.079943] mmc1: SDHCI controller on sdhci-tegra.2 [sdhci-tegra.2] using ADMA

<6>[ 5.080140] [mmc]:mmc_rescan:2083 mmc1: gpio_69:0 rescan_disable 0

<6>[ 5.080270] [mmc]:sdhci_tegra_probe:1109 mmc2: non-built_in 0

<6>[ 5.081343] sdhci-tegra sdhci-tegra.0: Error: tegra3 io dpd not supported for sdhci-tegra.0

<4>[ 5.082432] mmc2: Invalid maximum block size, assuming 512 bytes

<6>[ 5.082578] mmc2: no vmmc regulator found

<6>[ 5.083722] [mmc]:mmc_power_off:1436 mmc2:vdd_slot_reg: use_count 1

<6>[ 5.083845] [mmc]:mmc_power_off:1439 mmc2:vdd_io_reg: use_count 0

<6>[ 5.086113] [mmc]:mmc_detect_change:1587 mmc2: gpio_69:1

<6>[ 5.086243] [mmc]:mmc_schedule_delayed_work:87 mmc2: delay 0

<6>[ 5.086318] mmc2: SDHCI controller on sdhci-tegra.0 [sdhci-tegra.0] using ADMA

<6>[ 5.087607] tegra-se tegra-se: tegra_se_probe: complete

<6>[ 5.087935] sis_init

<6>[ 5.088357] sis_init : ret = 0

<6>[ 5.088629] usbcore: registered new interface driver usbhid

<6>[ 5.088702] usbhid: USB HID core driver

.....

<6>[ 5.180065] [mmc]:mmc_decode_cid:113 cid.prv 0x6f

<6>[ 5.191626] [mmc]:mmc_read_ext_csd:285 ext_csd.sectors 0x3b34000 prod_name HYNIX BOOT_SIZE_MULTI 0x10

<4>[ 5.210624] mmc0: switch to bus width 1 ddr 0 failed

<3>[ 5.210708] mmc0: error -110 whilst initialising MMC card

<6>[ 5.320347] [mmc]:mmc_decode_cid:113 cid.prv 0x6f

<6>[ 5.336772] [mmc]:mmc_read_ext_csd:285 ext_csd.sectors 0x3b34000 prod_name HYNIX BOOT_SIZE_MULTI 0x10

<4>[ 5.367118] mmc0: switch to bus width 1 ddr 0 failed

<3>[ 5.367194] mmc0: error -110 whilst initialising MMC card

<6>[ 5.501464] [mmc]:mmc_decode_cid:113 cid.prv 0x6f

<6>[ 5.523889] [mmc]:mmc_read_ext_csd:285 ext_csd.sectors 0x3b34000 prod_name HYNIX BOOT_SIZE_MULTI 0x10

<4>[ 5.543424] mmc0: switch to bus width 1 ddr 0 failed

<3>[ 5.543505] mmc0: error -110 whilst initialising MMC card

.....

if I found a solution i'll be back here !