Greetings. Any assistance would be greatly appreciated. If this has been fixed or resolved and I somehow missed the fix, I apologize as I haven't been able to fix this.

HW: Raspberry Pi 4 SD: Samsung Pro Endurance 128
I completed a fresh Slackware ARM current installation following the excellent guide I found at SARPI, and after the first reboot, I was able to successfully ssh into my pi4.

I then completed the step to configure slackpkg and then the following slackpkg install-new followed by upgrade-all,

I then rebooted my pi4, and I have been unable to ssh into it since, either remotely via PuTTY or locally from the command-line ssh on the pi4.

When I attempt to ssh from the command-line, ssh -v localhost, I get

debug1: expecting SSH2_MSG_KEX_ECDH_REPLY

followed by
ssh_dispatch_run_fatal.

Thank you!

The issue appears to be resolved? I ran slackpkg again and was greeted with a message that I needed a new slackpkg.conf file as mine was old. I mv the current to .old and .new to slackpkg.conf. I then executed slackpkg update,slackpkg install-new (there were no new packages to be installed), and finally, slackpkg upgrade-all. I received a message that there were new packages available, but that they were cached locally. I selected yes to upgrade-all and went away for several hours. On a whim, I tried to connect from the command line, ssh -v {ipaddress} of the pi4 which was successful, and no debug1: expecting SSH2_MSG_KEX_ECDH_REPLY message. I then attempted to connect remotely via putty and connected successfully. The upgrades are still running. Hopefully, when I reboot, I will still be able to connect. It appears that when slackpkg upgrade interrupted a package that ssh2 depended on. I will post again after I reboot. I most certainly will upgrade slackpkg first off when I bring up my next rpi4.

For what it's worth, if/when I am using slackpkg upgrade-all (i.e. me being lazy) I look through the list of all available pkgs and check for any slackpkg updates. If there is a new slackpkg version I will install it and only that pkg on its own. After the new slackpkg has been installed and configured I will upgrade-all the other pkgs.

In the past there's been a couple of occasions where the upgrade-all process didn't go entirely as expected, and I have found that doing it the way I've described is very reliable (thus far). You might like to try this method for future upgrades and see if it also works for you.