root@GL-AXT1800:~# cat /proc/mtd 
dev:    size   erasesize  name
mtd0: 00180000 00020000 "0:SBL1"
mtd1: 00100000 00020000 "0:MIBIB"
mtd2: 00380000 00020000 "0:QSEE"
mtd3: 00080000 00020000 "0:DEVCFG"
mtd4: 00080000 00020000 "0:RPM"
mtd5: 00080000 00020000 "0:CDT"
mtd6: 00080000 00020000 "0:APPSBLENV"
mtd7: 00180000 00020000 "0:APPSBL"
mtd8: 00080000 00020000 "0:ART"
mtd9: 07280000 00020000 "rootfs"
mtd10: 00080000 00020000 "log"
mtd11: 00080000 00020000 "0:ETHPHYFW"
mtd12: 0041e000 0001f000 "kernel"
mtd13: 034ad000 0001f000 "ubi_rootfs"
mtd14: 03339000 0001f000 "rootfs_data"

暴力搜索，查到在 mtd8

root@GL-AXT1800:/dev# hexdump -C /dev/mtdblock8 
*
00000090  43 4f 55 4e 54 52 59 3a  43 4e ff ff ff ff ff ff  |COUNTRY:CN......|

导出

dd if=/dev/mtdblock8 of=mtdblock8
cp mtdblock8 mtdblock.orig

修改，opkg里没有 hexedit，但是有个 jupp

opkg update
opkg install jupp
jupp mtdblock8

比较难用，ctrl + o + g 进入16进制模式，把 COUNTRY:CN 改成 COUNTRY:US ，再使用 ctrl + k + x 保存。可以看 ctrl + j 的帮助。

回写，重启

dd if=mtdblock8 of=/dev/mtdblock8
reboot