I recently bought a second hand Linksys WRT1900ACS (version 1). I've been experimenting so far with DD-WRT (been a long time user) and I am not really happy with how this is working out.
From what I researched, this router has two partitions. Partition 1 is where the current DD-WRT installation is stored and Partition 2 is the Linksys firmware. I have to use Putty to switch to the Linksys partition.
How can I safely update to OpenWRT from DD-WRT? I'm concerned that if i switch to the second partition where the stock firmware is installed and then install OpenWRT, it would overwrite it. And if ever something happens, I won't be able to fallback to the stock firmware
Directions you'll get from here advise starting all OpenWrt install procedures from stock firmware - so there's no generally accepted answer to your question.
you need flash openwrt factory, from the Linksys web interface. and after that if you like have on one partition official Linksys firmware, just do not flash the sysupgrade.
1)make sure you have the router on the partition of official Linksys firmware.
2) flash openwrt factory. that way you have openwrt on one partition, and Linksys firmware on the other.
reboot the router so it will be on official Linksys firmware partition.
flash openwrt factory.
the Linksys routers, never will flash the partition that you are working on.
4)if you flash openwrt from ddwrt partition, you will loose the official firmware on first and second partition.
you can do the same with the official firmware, just flash the official firmware from the partition that you have the official firmware now. that way the two partitions will be on official firmware, and than you can flash openwrt factory.
now you have factory openwrt on one partition, and Linksys on the other.
yes, if you like one partition with official firmware, you need flash a new factory openwrt from Linksys partition.
never flash a sysupgrade.bin from Linksys partition.
a sysupgrade need be flashed from openwrt factory partition. but this way you ll have openwrt-sysupgrade on one partition, and openwrt factory on the other.
hope that is clear.