OK redone uboot and boot.{txt,scr} that should have the other errors. You can download from:
http://davidjohnsummers.uk/TBS.tar.gzInstructions in the README.
Think I've got to the bottom of why the eMMC doesn't work, looks like we need to enable dwmmc@ff0d0000 - this is enabled on the TinkerOS. Its set in neither u-boot not the tinker device tree.
When I know what your set up comes up like, we can set it in the boot.{txt,scr}. Then if linux detects the eMMC, we can look at getting it to work in u-boot. Also try and mainline the device tree.
When you get boot messages through to 4 seconds, I recon your linux has come up, especially if the heartbeat led is flashing. I think the problem is that it doesn't start a terminal on ttyS2 - so I've given you the command to do that. Otherwise, plug in the ethernet, find its address, and ssh into the box ...
You ask for the u-boot configuration I used. Its close to the standard tinker-rk3288_defconfig. Think I added the boot command and the device tree ...
$this->bbcode_second_pass_code('', 'CONFIG_ARM=y
CONFIG_ARCH_ROCKCHIP=y
CONFIG_SYS_TEXT_BASE=0x00000000
CONFIG_SYS_MALLOC_F_LEN=0x2000
CONFIG_ROCKCHIP_RK3288=y
CONFIG_SPL_ROCKCHIP_BACK_TO_BROM=y
CONFIG_TARGET_TINKER_RK3288=y
CONFIG_DEBUG_UART_BASE=0xff690000
CONFIG_DEBUG_UART_CLOCK=24000000
CONFIG_SPL_STACK_R_ADDR=0x80000
CONFIG_DEFAULT_DEVICE_TREE="rk3288-tinker"
CONFIG_DEBUG_UART=y
CONFIG_BOOTCOMMAND="run distro_bootcmd"
# CONFIG_ANDROID_BOOT_IMAGE is not set
CONFIG_SILENT_CONSOLE=y
CONFIG_CONSOLE_MUX=y
# CONFIG_DISPLAY_CPUINFO is not set
CONFIG_DISPLAY_BOARDINFO_LATE=y
CONFIG_SPL_STACK_R=y
CONFIG_SPL_STACK_R_MALLOC_SIMPLE_LEN=0x2000
CONFIG_SPL_I2C_SUPPORT=y
CONFIG_CMD_GPIO=y
CONFIG_CMD_GPT=y
CONFIG_CMD_I2C=y
CONFIG_CMD_MMC=y
CONFIG_CMD_SF=y
CONFIG_CMD_SPI=y
CONFIG_CMD_USB=y
# CONFIG_CMD_SETEXPR is not set
CONFIG_CMD_CACHE=y
CONFIG_CMD_TIME=y
CONFIG_CMD_PMIC=y
CONFIG_CMD_REGULATOR=y
# CONFIG_SPL_DOS_PARTITION is not set
# CONFIG_SPL_EFI_PARTITION is not set
CONFIG_SPL_PARTITION_UUIDS=y
CONFIG_SPL_OF_CONTROL=y
CONFIG_OF_SPL_REMOVE_PROPS="pinctrl-0 pinctrl-names clock-names interrupt-parent assigned-clocks assigned-clock-rates assigned-clock-parents"
CONFIG_ENV_IS_IN_MMC=y
CONFIG_REGMAP=y
CONFIG_SPL_REGMAP=y
CONFIG_SYSCON=y
CONFIG_SPL_SYSCON=y
# CONFIG_SPL_SIMPLE_BUS is not set
CONFIG_CLK=y
CONFIG_SPL_CLK=y
CONFIG_FASTBOOT_FLASH=y
CONFIG_FASTBOOT_FLASH_MMC_DEV=0
CONFIG_FASTBOOT_CMD_OEM_FORMAT=y
CONFIG_ROCKCHIP_GPIO=y
CONFIG_SYS_I2C_ROCKCHIP=y
CONFIG_MISC=y
CONFIG_I2C_EEPROM=y
CONFIG_MMC_DW=y
CONFIG_MMC_DW_ROCKCHIP=y
CONFIG_DM_ETH=y
CONFIG_ETH_DESIGNWARE=y
CONFIG_GMAC_ROCKCHIP=y
CONFIG_PINCTRL=y
CONFIG_SPL_PINCTRL=y
# CONFIG_SPL_PINCTRL_FULL is not set
CONFIG_PINCTRL_ROCKCHIP_RK3288=y
CONFIG_DM_PMIC=y
CONFIG_PMIC_RK8XX=y
CONFIG_DM_REGULATOR_FIXED=y
CONFIG_REGULATOR_RK8XX=y
CONFIG_PWM_ROCKCHIP=y
CONFIG_RAM=y
CONFIG_SPL_RAM=y
CONFIG_DEBUG_UART_SHIFT=2
CONFIG_SYSRESET=y
CONFIG_USB=y
CONFIG_USB_DWC2=y
CONFIG_ROCKCHIP_USB2_PHY=y
CONFIG_USB_STORAGE=y
CONFIG_USB_GADGET=y
CONFIG_USB_GADGET_MANUFACTURER="Rockchip"
CONFIG_USB_GADGET_VENDOR_NUM=0x2207
CONFIG_USB_GADGET_PRODUCT_NUM=0x320a
CONFIG_USB_GADGET_DWC2_OTG=y
CONFIG_USB_FUNCTION_MASS_STORAGE=y
CONFIG_USB_HOST_ETHER=y
CONFIG_USB_ETHER_ASIX=y
CONFIG_USB_ETHER_SMSC95XX=y
CONFIG_USE_TINY_PRINTF=y
CONFIG_CMD_DHRYSTONE=y
CONFIG_ERRNO_STR=y
CONFIG_OF_LIBFDT=y
')