PowerCloud Systems CR5000 - Openwrt install issue


I tried to install openwrt firmware on PowerCloud Systems CR5000 router which is can not be used now as the cloud service has been stopped so that I can reuse this router with new interface.

I successfully copied openwrt-19.07.3-ath79-generic-pcs_cr5000-squashfs-sysupgrade.bin file using tftp server on my laptop and bootloader as tftp client renaming the file as ap.bin.
Here is the log :

Warning: Anticipation window in use
Connection received from on port 2268 [09/07 17:28:53.742]
Read request for file <ap.bin>. Mode octet [09/07 17:28:53.743]
OACK: <timeout=4,> [09/07 17:28:53.744]
Using local port 63830 [09/07 17:28:53.744]
<ap.bin>: sent 8186 blks, 4194581 bytes in 1 s. 0 blk resent [09/07 17:28:54.318]

But, router still shows OLD CR5000 control panel.

Please advise.