[Lenny400] LetuxOS on SD card for MIPS JZ4780 CI20

H. Nikolaus Schaller hns at goldelico.com
Thu Apr 18 18:25:36 CEST 2019

Hi Paul,

> Am 14.04.2019 um 13:15 schrieb Paul Boddie <paul at boddie.org.uk>:
> On Sunday 14. April 2019 09.32.19 H. Nikolaus Schaller wrote:
>> I have now checked with
>> https://www.elinux.org/CI20_Hardware#Dedicated_UART_header and my FTDI is
>> connected to the primary expansion header:
>> pin 6	black	GND
>> pin 8	white	UART0_TXD
>> pin 10	green	UART0_RXD
>> (nc)	red	USB +5V - BTW: it should be possible to connect to pin 2/4 and
>> power the board through the FTDI USB...

Yes, it works to power the board through the FTDI adapter so that I only need one cable :

>> So I have no UART4 connected and in use. Is this the white JST connector?
> Yes, I think so, according to the pinout at precisely the position in the page 
> referenced by the link you gave:
> https://www.elinux.org/CI20_Hardware#Dedicated_UART_header
> I found that the pins were not usable with the female jumper wires used by my 
> USB serial adapter (intended for the Raspberry Pi): the wires were too loose 
> for the pins. The CI20 is a bit of an odd board with regard to some of the 
> design choices, but maybe there are products that need this kind of connector.

I spent some more minutes and it looks as if the official u-boot source
recommended here


does not support device tree at all. Which U-Boot are you using on SD card?
Where did you get it from or how did you build it?

Best regards,

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