Hi @metsys,
My guess is that all current Lede/OpenWrt images are to large and therefor fail Image checksum of the bootloader the fix is not changing the checksum but creating a smaller image readon.
Having the exact same model/version and PCB, I used the telnet backdoor in the original firmware to find out the size of the firmware partition which must be smaller than 3080192 bytes.
./telnetenable 192.168.1.250 AABBCCDDEEFF Gearguy Geardog
telnet 192.168.1.250
Trying 192.168.1.250...
Connected to 192.168.1.250.
Escape character is '^]'.
BusyBox v0.60.0 (2011.03.31-19:56+0000) Built-in shell (msh)
Enter 'help' for a list of built-in commands.
# cat /proc/mtd
dev: size erasesize name
mtd0: 00040000 00010000 "boot"
mtd1: 002f0000 00010000 "linux"
mtd2: 002658bc 00010000 "rootfs"
mtd3: 00010000 00010000 "ML1"
mtd4: 00010000 00010000 "ML2"
mtd5: 00010000 00010000 "ML3"
mtd6: 00010000 00010000 "ML4"
mtd7: 00010000 00010000 "ML5"
mtd8: 00010000 00010000 "ML6"
mtd9: 00010000 00010000 "ML7"
mtd10: 00010000 00010000 "ML8"
mtd11: 00010000 00010000 "T_Meter1"
mtd12: 00010000 00010000 "T_Meter2"
mtd13: 00010000 00010000 "POT"
mtd14: 00010000 00010000 "board_data"
mtd15: 00010000 00010000 "nvram"
# cat /dev/mtd/1 > /tmp/mtd1.img
# cat /dev/mtd/2 > /tmp/mtd2.img
# ls -la /tmp/mtd*
-rw-r--r-- 1 0 0 2513084 Dec 27 16:34 /tmp/mtd2.img
-rw-r--r-- 1 0 0 3080192 Dec 27 16:34 /tmp/mtd1.img
Followed by making a very tiny custom Lede 17.01.7 image around ~3MB insize which does flash correctly by using the following image builder command:
#imagebuilder very tiny without wifi
make image PROFILE="netgear-wn3000rp" PACKAGES="-wpad-mini -hostapd-common uhttpd uhttpd-mod-ubus libiwinfo-lua luci-base luci-app-firewall luci-mod-admin-full luci-theme-bootstrap -ppp -ppp-mod-pppoe -ip6tables -odhcp6c -kmod-ipv6 -kmod-ip6tables -odhcpd-ipv6only -odhcpd"
After the very tiny custom Lede image you may flash a larger Lede/OpenWrt image max 3735552 (look up the mtd size in Lede/Openwt) with drivers for wifi, however the 'b43' and 'wl' did not work in Lede 17.01.7.
#imagebuilder b43 wifi
make image PROFILE="netgear-wn3000rp" PACKAGES="kmod-b43 wpad-mini hostapd-common uhttpd uhttpd-mod-ubus libiwinfo-lua luci-base luci-app-firewall luci-mod-admin-full luci-theme-bootstrap -ppp -ppp-mod-pppoe"
DMESG b43 error
[ 15.899842] b43-phy0: Broadcom 5357 WLAN found (core revision 28)
[ 15.907361] b43-phy0: Found PHY: Analog 9, Type 4 (N), Revision 9
[ 15.913595] b43-phy0 ERROR: FOUND UNSUPPORTED RADIO (Manuf 0x17F, ID 0x2057, Revision 5, Version 2)
WL driver example
#imagebuilder wl wifi
make image PROFILE="netgear-wn3000rp" PACKAGES="-wpad-mini -hostapd-common kmod-brcm-wl wl wlc nas uhttpd uhttpd-mod-ubus libiwinfo-lua luci-base luci-app-firewall luci-mod-admin-full luci-theme-bootstrap -ppp -ppp-mod-pppoe" #not working/detecting
Maybe others would like to test b43 without luci in OpenWrt 19.07.x and or the brcm f/s mac drivers. Remember that for current OpenWrt you have to drop luci webinterface and maybe more packages before you may get an image smaller than 3735552 bytes.
Interesting fact about this device is that both with stock firmware and with lede/openwrt there is a eth0 switch configured with 2 ports although there is only one physical port!
I might add a wiki page for this device but will not continue effort.