TFTPD32 is not working with my RB751G (it was working with my RB150 and people report its working with RB4xx, but not with RB7xx, which is
strange, considering all RouterBoots should share a large part of codebase), so I fixed it:
Download fixed TFTPD32 / TFTPD64 4.0 (tftpd32_mikrotik.7z)
Original version is replying with DHCPOFFER packets to Mikrotik BOOTP request packets (which it seems to ignore), so basically I’m skipping DHCP_MESSAGE_TYPE option in response to BOOTP requests and it works (probably there is be an easier way if your routeros is working - by switching routerboot to DHCP mode from winbox or any other ui/terminal).
Personally, I needed TFPD32 + RouterBoard Network Booting to work to be able to run Open WRT on my board. Open WRT was required since at the moment RouterOs doesn’t support Telstra 4G (ZTE MF821) USB stick and support is not even replying (for a week now 
) to my request for adding it (stick works like any other 3G modem, so they need only to add some VID/PIDs to several places).
Results are exciting so far - MF821 works perfectly on RB751G with OpenWRT (using build from this topic (mirror on openwrt forum)). At this build (based on svn 30025) it is already supported by usb-modeswitch (don’t forget to instal usb-modeswitch-data package), so you only need to install and configure it and several other usual packages (guide) (basically kmod-usbserial, ppp, chat, comgt…) required for 3g modems to work.
After installing packages modify /etc/modules.d/60-usb-serial to :
usbserial vendor=0x19d2 product=0x0257
And edit wan interface definition inside /etc/config/network to something like:
config ‘interface’ ‘wan’
option ‘ifname’ ‘ppp0’
option device /dev/ttyUSB1
option apn telstra.internet
option service umts
option ‘proto’ ‘3g’
If you want to use minicom (to send some AT commands to force 4g mode or anything else) it responds on /dev/ttyUSB3.
There is a nice guide on configuiring Telstra 4G (ZTE MF821) on Linux, which is very similar thing.
