When copying out the commands from https://openwrt.org/toh/aruba/ap-303h, if you copy the multiline entry it will past into the env with a / appended at the end of each line.
You need to ensure its on one line.
For example;
*setenv ramboot_openwrt "run bootargs_openwrt;*
* setenv ipaddr 192.168.1.105; setenv serverip 192.168.1.75;*
* netget; set fdt_high 0x87000000; bootm*
should be pasted in as
*setenv ramboot_openwrt "run bootargs_openwrt; setenv ipaddr 192.168.1.105; setenv serverip 192.168.1.75; netget; set fdt_high 0x87000000; bootm"*
I had the same issue myself and a process of elimination fixed it.