Flash memory 16M is almost unknown : BoHong bh25q128as replaced by a Macronix 32MB
no problem with flash boot ( tftp -> console 2 ... ) for flash old 16M content
build new firmware for 32M flash memory
for read old content : CH341 -> NeoProgrammer_2.1.0.19
after write content in as MX25L25635E or WINBOND 256MB
startup -> tftp key 2 .... OpenWrt firmware
firstboot -> reboot -f
Variant for 32M version
modify in mt7621.mk
IMAGE_SIZE := 32448k
modify in mt7621_tenbay_t-mb5eu-32M.dts
reg = <0x90000 0x1F70000>
build
flash new firmware with tftp
if you have a USB NTFS problem:with ntfs-3g
solved with ln -s /usr/bin/ntfs-3g /sbin/mount.ntfs
reboot
If you have a problem for AP <-> Client solved with last fix