把荔枝派插入到电脑上，电脑上能看到有这个 USB 设备

$ lsusb
Bus 001 Device 016: ID 1f3a:efe8 Onda (unverified) V972 tablet in flashing mode

然后编译专用版本的 sunxi-tools，其他版本可能无法正常识别 F1C100s

$ git clone https://github.com/Icenowy/sunxi-tools.git -b f1c100s-spiflash
$ cd sunxi-tools
$ make

$ sudo ./sunxi-fel ver
AWUSBFEX soc=00001663(F1C100s) 00000001 ver=0001 44 08 scratchpad=00007e00 00000000 00000000

$ sudo ./sunxi-fel -l
USB device 001:013   Allwinner F1C100s

再编译专门适配 Nano 的 u-boot，编译成功后运行就行了

$ git clone https://github.com/Lichee-Pi/u-boot.git -b nano-v2018.01
$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- licheepi_nano_defconfig
$ make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- -j8

$ sudo ../../Icenowy/sunxi-tools/sunxi-fel uboot u-boot-sunxi-with-spl.bin

U-Boot SPL 2018.01-05676-g00188782ee (May 31 2018 - 11:40:24)
DRAM: 32 MiB
Trying to boot from FEL


U-Boot 2018.01-05676-g00188782ee (May 31 2018 - 11:40:24 +0800) Allwinner Technology

CPU:   Allwinner F Series (SUNIV)
Model: Lichee Pi Nano
DRAM:  32 MiB
MMC:   SUNXI SD/MMC: 0
Card did not respond to voltage select!
mmc_init: -95, time 22
*** Warning - MMC init failed, using default environment

In:    serial@1c25000
Out:   serial@1c25000
Err:   serial@1c25000
Net:   No ethernet found.
starting USB...
No controllers found
Hit any key to stop autoboot:  0