Hi,

I want to do something with the GPIOs 18 and 19 but I cant export them. With other GPIOs (1, 13, 14, 15, 16, 20, 21, 22) it is working but especially this two cant be exported.
I use this commands:
echo 18 > /sys/class/gpio/export
echo 19 > /sys/class/gpio/export

but it prompts:
ash: write error: Device or resource busy

Maybe there is a module which is blocking them?
I looked in the /etc/modules.d directory, but there is nothing which looks like an I2C module

02-crypto-hash 20-usb-core 30-fs-vfat 42-ipt-nat
03-crypto-manager 21-lib80211 30-ppp 45-ipt-nathelper
09-crypto-arc4 21-mac80211 40-fs-msdos 50-ledtrig-netdev
20-cfg80211 25-nls-cp437 40-ipt-core 50-wdt-ath79
20-eeprom-93cx6 25-nls-iso8859-1 40-pppox 60-leds-gpio
20-lib-crc-ccitt 25-nls-utf8 40-scsi-core 60-usb-storage
20-lib-crc-itu-t 26-ath 40-usb2
20-nls-base 27-ath9k-common 41-ipt-conntrack
20-scsi-core 28-ath9k 41-pppoe

Do you have any idea how to export them?

If there someone with the same Problem.
It seems like this is a firmware problem. Flashing a new firmware build on the carambola solves the problem according to https://github.com/8devices/carambola2/issues/65

But if someone has a simpler approach, please tell me