Why are ips not reset after resetting openwrt from recovery mode?

Question

linux

On a router with openwrt, dhcp issues ips to all my devices.
Wanted to reset openwrt. Entered the recovery mode:
mount_root
mtd -r erase rootfs_data
After the restart, all reset packages removed asks for a password. Everything seems to be ok, but again the same ip turned out to be the same ip as they were before the router was reset. How is this even possible, I rubbed all the rutfs.
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tplink 842nd v2 / openwrt 14.07BB

Answer 1

When communicating between a client and a server using the DHCP protocol, the client in the options field indicates the last IP address issued to the client. That is, the client computer remembers its last received address and reports it to the dhcp server. The DHCP server can ignore this field and issue any address from the range, but in most cases it will check and try to issue the old address.
Read more about how the DHCP protocol works: https://ru.wikipedia.org/wiki/DHCP
The answer to your question begins with the words "Let's consider an example of the process of obtaining an IP address by a client from a DHCP server."

Answer 2

and the fact that when issuing an IP on computers, the time of the lease comes does not bother you? just either reboot the switch, or disable the network card and enable