R36S: console hangs at boot when the second SD card (TF2) is inserted A workaround for R36S consoles (RK3326) running ArkOS that won't boot with TF2 inserted. It needs no kernel rebuild and no initramfs change.
Symptoms The console boots fine with TF1 (system card) only. With TF2 (ROMs card) inserted at power-on, boot hangs. If TF2 is inserted after ArkOS has booted, it works perfectly. dmesg may show mmc1: error -123 whilst initialising SD card with retries at 300/200/100 kHz, and systemd timeouts on /dev/mmcblk1p1. Reformatting TF2 (exFAT, NTFS, a new partition table), editing fstab, capping the frequency at 50 MHz, removing UHS modes, broken-cd, and setting 8 mA drive strength on the pins did not help.