It booted and seems to be running fine. Space is a bit tight : only 76k flash free with my smallish scripts loaded.
Boot log except and free info below.
OpenWrt 18.06.0-rc1 r7090-d2aa3a1b62 / LuCI openwrt-18.06 branch (git-18.163.60998-c379f00)
[ 0.000000] Linux version 4.9.109 (buildbot@builds-03.infra.lede-project.org) (gcc version 7.3.0 (OpenWrt GCC 7.3.0 r6984-fa0275b) ) #0 Thu Jun 21 05:02:51 2018
[ 0.000000] MyLoader: sysp=4cc15e57, boardp=635a7dca, parts=0c7b9213
[ 0.000000] bootconsole [early0] enabled
[ 0.000000] CPU0 revision is: 00019374 (MIPS 24Kc)
[ 0.000000] SoC: Atheros AR9330 rev 1
[ 0.000000] Determined physical RAM map:
...
[ 0.000000] Kernel command line: board=TL-WR741ND-v4 console=ttyATH0,115200 rootfstype=squashfs noinitrd
[ 0.000000] PID hash table entries: 128 (order: -3, 512 bytes)
[ 0.000000] Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
[ 0.000000] Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
[ 0.000000] Writing ErrCtl register=00000000
[ 0.000000] Readback ErrCtl register=00000000
[ 0.000000] Memory: 27660K/32768K available (3356K kernel code, 159K rwdata, 424K rodata, 212K init, 219K bss, 5108K reserved, 0K cma-reserved)
free
total used free shared buffers cached
Mem: 27872 23312 4560 488 2224 7652
-/+ buffers/cache: 13436 14436
Swap: 0 0 0