Thanks a lot for the hard work!
I just test it , but it looks like a path (or something like that) setting is not correct.
I try to use sudo, git etc. commands, but they did not work.(command not found). I'm a newbee in linux, so maybe I do something wrong. 
I tried to install this:
By the way...is there a easy way to instal a recent version of nodejs?
-I also see only 4 ports in Switch
.Thanks again!!
Thanks for the explanation and the quick response.
There was a time in my career as a software engineer I knew stuff, but now I find I'm running a bit behind the curve... 
In my last attempt did upload EA9500_Factory.trx to nflash0.trx2 but did not know about or try setting nvram options. I'll give that a try; fingers crossed... I assume that the nvram options should be set after loading the trx file?
The instructions you linked require you to build OpenWrt from scratch to compile Node.js in feeds - you can do so by using the EA9500 support packages in my Github.
Also, the reason you only see 4 ports in switch configuration is because this is a swconfig-based build.
Ports 1, 2, 3, 5, and 6 are connected to the external BCM53125 switch (listed as LAN1 in OpenWrt) that acts as a dumb switch (but will passthrough any VLANs assigned to it)
Yes, set the nvram option to boot from the failsafe partition after flashing the EA9500_Factory.trx file.
Ok, well compiling is going to have to wait due to other time demands and my needing to learn a bit more about compiling Node.js - new territory, though relevant to a RPi project I'm starting on. I ran across your github entries yesterday and being ignorant, decided to hold off.
Based on what you've said I'm guessing the kernel panic, SQUASHFS error: xz_dec_run error, data probably corrupt, etc., are related, and the cascading error messages are similar in nature to a C compiler running past a missing ";" and generating line-after-line of errors.
I have spent time trying to sort through the various postings, but given my current level of knowledge I'm not able to separate out the chaff from the wheat. Any recommendations on tutorials/step-by-step for Dummies to learn how to do this work in a structured fashion?
FWIW, I did log the boot-up in a captured text file, but again, my lack of knowledge impedes my ability to sort through all the data.
Thanks again for your time. 
The instructions to build OpenWrt to run Node.js were for jvr, who was trying to run some sort of mqtt broker on their EA9500.
If you have a boot log of the stock firmware or Openwrt flashed to nflash0.trx2 and set to boot from there, please put it up on a Pastebin and maybe we can figure out what's wrong with your EA9500.
I've posted to pastebin.com
Title: Linksys ea9500 repeat reboot
User: NurseBob
Link: https://pastebin.com/PsTee0Vq
Did you set nvram set bootpartition=1?
Seems like your EA9500 still booted to the main OS partition nflash0.os as seen in this line:
Loader:raw Filesys:raw Dev:nflash0.os File: Options:(null)
I thought I had. Will do so again.
set to new partition; problem persists...
new pastebin file: Linlksys EA9500 rebooting 02
Long day for me. Will check back in the morning.
Thanks again for your time and effort.
Bob
Any further ideas regarding my ea9500?
Thanks
Flash the following. Make sure you make a note of current Mac addresses and update it in the nvram later. Remind me if you are using a US model. If so I can send you dumps from mine.
I would flash one partition at a time below and check if it works. Don't flash the CFE, I think it's fine.
VERY IMPORTANT: Check your serial cable. Don't assume if it can read properly it can write correctly.
nflash0.nvram
nflash0.devinfo
nflash0.trx
nflash0.trx2
nflash1.brcmnand
Total flash size = 128mb (less 256k for cfe)
To my great dismay and embarassment, this was all due to pilot error! Basically a CFIT moment. Luckily the router was robust enough to tolerate my stupid mistake. Due to massive interior home changes & painting contractor in every room, I had to relocate all of my network gear multiple times. On the last move I managed to plug a D-Link 5V power supply into the Linksys, which I just noticed this afternoon. 
Connecting the proper supply "repaired" all of my problems. 
So, very lucky in that regard. I don't know about the router, but in my experiences programming various microcontrollers I know that low voltage can impair saving to flash. That may have saved me from even more problems.
I deeply appreciate all of the efforts on my behalf. Brings back distant memories of my own experiences doing tech support for Del Monte Foods when I was working as a software engineer.
All my best to all here who helped.
kinda off topic but lmao, yeah, I've been the victim of similar sized barrel connectors before. Took me a month to figure out why my Linksys EA6900 kept rebooting - turns out I gave it 9V/1.5A instead of 12V/2A.
Pretty impressive how the internal buck converters can still tolerate a supply that low and keep it running for a few hours off that though!
how to install a package whose dependency requires a different kernel version? Specifically, I tried to install minidlna, which depends on kmod-sound-core. The kernel required for this package is 4.14, while we are using 4.19 now.
Error message:
The installed version of package kernel is not compatible, require 4.14.162-1-dd51dd4f… while 4.19.91-1-a72ba6d6… is installed.
Thanks
You can't, it's as simple as that. If you need additional kernel modules, you need to sysupgrade to a newer version and install them very soon.
How do I make a kmod-sound-core package for kernel4.19? The default seems to be for 4.14.
The reason you won't be able to update the package is because official OpenWrt kernel for bcm53xx platform is still on 4.14
KERNEL_PATCHVER:=4.14
Thanks for the explanation. Is there a way to migrate to 4.19 for a certain package? I saw your patch for 4.19 and I wonder if there is something I could do to get this working.
Just wondering, is the switch limitation (communication only possible between specific ethernet ports) still present? Thanks.
I don't think it should exist now, Please check.