Provided by: sunxi-tools_1.4.2+git20220212.08e209-1_amd64 

NAME
sunxi-fel - controlling USB BootROM protocol for Allwinner CPUs
SYNOPSIS
sunxi-fel [OPTIONS] COMMAND [ARGS]
DESCRIPTION
sunxi-fel is a script interface for USB communication with the BootROM of Allwinner CPUs.
On explicit request (typically by pressing a button often labeled "uboot" or "recovery"), or when all
other booting methods fail, the CPU's early ROM code enters the so called FEL mode, where it will wait
for USB commands sent by some host to the Allwinner CPU's USB OTG interface. sunxi-fel implements this
FEL protocol and communicates with the ROM code, to download or upload data and to start code execution.
Besides simply allowing to write to or to read from device memory, sunxi-fel also helps with more complex
things, which involve uploading code, executing it and then returning to FEL mode, to allow further data
transfer or inspection. In particular it supports loading and executing U-Boot, including the primary
SPL stage.
OPTIONS
Those options affect general execution and should be put first, before any actual commands.
-h, --help
Print a help message and exit.
-v, --verbose
Enable verbose logging.
-p, --progress
"write" transfers show a progress bar.
-l, --list
Enumerate all (USB) FEL devices and exit.
-d, --dev bus:devnum
Use specific USB bus and device number
--sid SID
Select a device by its SID key (exact match). The SID key of a particular device can be queried using
the "sid" command.
SUNXI-FEL COMMANDS
sunxi-fel can take several commands, each followed by their parameters, and will execute them in order.
The only exception is the "uboot" command, which will delay launching U-Boot until all other commands
have been executed.
Please note that accessing any part of the DRAM will not work until the DRAM controller has been
initialized. This can be achieved by uploading and executing a suitable U-Boot SPL image, using the "spl"
command. Trying to access DRAM before that will most likely hang.
Any numbers given as parameters to those commands can be prefixed with "0x" to denote hexadecimal
notation or "0" to start an octal number. They are interpretated as decimal numbers otherwise.
spl <filename>
Load and execute U-Boot SPL.
Upload the given binary file to the appropriate SRAM location, carefully moving the FEL stack out of
the way in the process. The binary is then executed. When it returns, the FEL stack is restored and
execution is transferred back to the BootROM's FEL routine.
If the file additionally contains a main U-Boot binary (u-boot-sunxi-with-spl.bin), this command also
transfers that to memory, using the load address stored in the image file, but won't execute it.
uboot <u-boot-sunxi-with-spl.bin>
like "spl", but actually starts U-Boot. U-Boot execution will take place when the fel utility exits.
This allows combining "uboot" with further "write" commands, to transfer other files possibly needed
for the boot.
hex[dump] <address> <length>
Hexadecimal memory dump. Dumps <length> bytes of the memory region starting at <address>. The context
will be displayed as a hexdump, suitable for human inspection.
dump <address> <length>
Binary memory dump. Dumps <length> bytes of the memory region starting at <address>. The context will
be dumped "as is" to the standard output, so it can be redirected to a file and processed as binary
data.
exe[cute] <address>
Start executing code at <address> in memory on the device.
reset64 <address>
Request a warm reset of the core, starting execution in the 64-bit AArch64 execution state, at
<address>.
memmove <dest> <source> <size>
Copy <size> bytes within device memory, from <source> to <dest>.
readl <address>
Read a 32-bit value from device memory at <address>. The value will be output as a hexadecimal
number, prefixed with "0x". The address needs to be 4-byte aligned.
writel <address> <value>
Write the given 32-bit <value> to device memory at <address>.
read <address> <length> <file>
Write memory contents into file. Reads <length> bytes from memory at <address> and writes the content
into <file>.
write <address> <file>
Store file contents into memory. Writes the entire content of <file> into memory at <address>.
write-with-progress <addr> <file>
Display a textual progress bar while writing to the device. Same as "write" with the "-p" parameter.
write-with-gauge <addr> <file>
Same as write, but write the progress in percentages to the standard output. This can be piped to
any "dialog" compatible program, when using the --gauge widget.
write-with-xgauge <addr> <file>
Same as write-with-gauge, but with extended gauge output. This can be piped to any "dialog"
compatible program, using the --gauge widget. Aside from updating the current progress in percents,
it also updates the number of bytes written and gives an estimated time to completion.
multi[write] # <addr> <file> ...
Like "write-with-progress", but with multiple load adddresses and files, all sharing the same
progress bar.
multi[write]-with-gauge ...
Like "write-with-gauge", but with multiple load adddresses and files, all sharing the same progress
bar.
multi[write]-with-xgauge ...
Like "write-with-xgauge", but with multiple load adddresses and files, all sharing the same progress
bar.
echo-gauge some text
Update prompt/caption for gauge output. This outputs a command to be interpreted by "dialog" to
change the caption text.
ver[sion]
Show the BROM version. This prints some static data, among other things containing the detected SoC.
Can be used to verify a FEL connection is working.
sid
Retrieve and output the 128-bit SID key. This key contains some form of serial number, which should
be unique to each chip (although there have been reports of same SIDs for particular batches of
chips).
sid-register
As the "sid" command above, but use the alternative MMIO register access method on the device. Some
SoCs require this method for reliable results.
clear <address> <length>
Clear <length> bytes of memory starting at <address> (filling with zeroes).
fill <address> <length> <value>
Fills <length> bytes of memory starting at <address> with the byte <value>.
spiflash-info
Retrieves basic information about a SPI flash chip attached to the SPI0 pins. This is using the same
method as the BootROM does, to accesses the same storage that the device could boot from.
Prints the manufacturer of the flash chip and its capacity. Should also be used to detect the
presence of a SPI flash chip.
spiflash-read <addr> <length> <file>
Reads <length> bytes starting from offset <addr> of a SPI flash chip, storing the result into <file>.
spiflash-write <addr> <file>
Reads <file> and stores its content in the SPI flash, starting at offset <addr>.
EXAMPLES
$ sunxi-fel -v -p ver
$ sunxi-fel uboot u-boot-sunxi-with-spl.bin
$ sunxi-fel -v -p spl sunxi-spl.bin write 0x44000 bl31.bin write 0x4a000000 u-boot.bin reset64
0x44000
AUTHOR
Andre Przywara <osp@andrep.de>
1.5 14 Jan 2022 sunxi-fel(1)