image: https://github.com/radxa-build/rock-3a/releases/download/20220701-0049/rock-3a-ubuntu-focal-server-arm64-20220701-0200-gpt.img.xz
/boot/uEnv.txt: overlays=rk3568-can1-m0 rk3568-pwm8-m0-fan rk3568-uart2-m0
In result the /dev/ttyS2 works, but bluetooth on /dev/ttyS1 stops working:
| default | disable fiq_debugger, enable uart | |
|---|---|---|
| m.2e uart1 bt | /dev/ttyS1: works hci0 | /dev/ttyS1: broke, no response |
| gpio uart2 console | /dev/ttyFIQ0: works, noisy | /dev/ttyS2: works, silent |
The brcm_patchram_plus doesn’t appear to receive anything:
$ echo 0 > /sys/class/rfkill/rfkill0/state; sleep 2; echo 1 > /sys/class/rfkill/rfkill0/state; sleep 2;
$ rfkill list
0: bt_default: Bluetooth
Soft blocked: no
Hard blocked: no
1: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
# AP6212
$ brcm_patchram_plus1 -d --enable_hci --no2bytes --use_baudrate_for_download --tosleep 200000 --baudrate 1500000 --patchram /system/etc/firmware/bcm43438a1.hcd /dev/ttyS1
option enable_hci
option no2bytes
option use_baudrate_for_download
option tosleep with arg 200000
option baudrate with arg 1500000
option patchram with arg /system/etc/firmware/bcm43438a1.hcd
/dev/ttyS1
proc_resetwriting
01 03 0c 00
writing
01 03 0c 00
# AP6236
$ brcm_patchram_plus -d --enable_hci --no2bytes --use_baudrate_for_download --tosleep 200000 --baudrate 1500000 --patchram /lib/firmware/brcm/BCM4343B0.hcd /dev/ttyS1
option enable_hci
option no2bytes
option use_baudrate_for_download
option tosleep with arg 200000
option baudrate with arg 1500000
option patchram with arg /lib/firmware/brcm/BCM4343B0.hcd
/dev/ttyS1
proc_resetwriting
01 03 0c 00
writing
01 03 0c 00
Note, this is reproducible with both AP6236 and AP6212. They did indeed work prior to /boot/uEnv.txt change.
It is possible to have console and bluetooth both. But disabling kernel console, the /dev/ttyS2 is returned, but negatively affects /dev/ttyS1 or bt_uart1 in mysterious way.