ok, have recovered my hame mpr-a2 again to almost full functionality - only web interface is missing, but this buggy luci with lua installation is too cumbersome.
Now I have ethernet, wireless and usb interfaces working, can access via telnet and it's enough for the moment. 4G usb dongle works fine and right now I'm having internet via the device.
Notes
1. I already had OpenWrt flashed some time ago when I had serial connection soldered.
2. This time I didn't have the serial connection and finally didn't need to disassemble the device.
3. MAC addresses are printed on labels on the device
4. The 4G usb dongle is configured for autoconnection and has built-in dhcp.
If it helpful to anybody, below are steps I finally followed to recover:
1. reset the device - using the small reset button (a needle or similar thing is needed). Changed IP on my PC to 192.168.1.2 and logged via telnet to the router with IP 192.168.1.1 (using ethernet interface, wifi by default is disabled after reset)
2. using vi modified the following configuration files in the /etc/config folder
- network
- wireless
- dhcp
Here are the configurations
==== network ====
config interface 'loopback'
option ifname 'lo'
option proto 'static'
option ipaddr '127.0.0.1'
option netmask '255.0.0.0'
config interface 'lan'
option ifname 'eth0.1'
option type 'bridge'
option proto 'static'
option ipaddr '192.168.0.70'
option gateway '192.168.0.250'
option dns '93.100.1.3'
option netmask '255.255.255.0'
option macaddr '9c:41:7c:21:73:08'
config interface 'wan'
option proto 'dhcp'
option macaddr '9c:41:7c:21:73:09'
option type 'bridge'
option _orig_ifname 'eth0.2 radio0.network1'
option _orig_bridge 'true'
option ifname 'eth0.1 eth0.2 usb0'
config switch
option name 'rt305x'
option reset '1'
option enable_vlan '1'
config switch_vlan
option device 'rt305x'
option vlan '1'
option ports '0 1 2 3 6t'
config switch_vlan
option device 'rt305x'
option vlan '2'
option ports '4 6t'
config interface 'usbwifi'
option type 'bridge'
option proto 'dhcp'
option _orig_ifname 'usb0'
option _orig_bridge 'true'
option ifname 'usb0'
config interface 'wwan'
option proto 'dhcp'
==== wireless ====
config wifi-device 'radio0'
option type 'mac80211'
option hwmode '11g'
option path '10180000.wmac'
option htmode 'HT20'
option channel '10'
option txpower '20'
option country '00'
config wifi-iface
option encryption 'psk2'
option device 'radio0'
option ssid 'hamewifi'
option key 'thesecretkey'
option mode 'ap'
option network 'usbwifi wwan'
==== dhcp ====
config dnsmasq
option domainneeded '1'
option boguspriv '1'
option localise_queries '1'
option rebind_protection '1'
option rebind_localhost '1'
option local '/lan/'
option domain 'lan'
option expandhosts '1'
option readethers '1'
option leasefile '/tmp/dhcp.leases'
option resolvfile '/tmp/resolv.conf.auto'
option enable_tftp '1'
option tftp_root '/tmp'
config dhcp 'lan'
option interface 'lan'
option start '100'
option limit '150'
option leasetime '12h'
option dhcpv6 'hybrid'
option ra 'hybrid'
option ndp 'hybrid'
config dhcp 'wan'
option interface 'wan'
option ignore '1'
config odhcpd 'odhcpd'
option maindhcp '0'
option leasefile '/tmp/hosts/odhcpd'
option leasetrigger '/usr/sbin/odhcpd-update'
config dhcp 'wan6'
option dhcpv6 'hybrid'
option ra 'hybrid'
option ndp 'hybrid'
option master '1'