Recently I needed a faster machine to compile natively binaries I would then run on the RPi Zero. I Have the RPi 4 so I thought it would be a good choice (some 6 times faster then the Zero) ... Went over to SARPI and found there is no support for slackwareARM 14.2 on the RPi 4. At first, a little disappointed, I started compiling on the Zero but soon was forced to think of a workaround.

I started thinking that the softfloat 14.2 userland would just never ask the kernel, compiled for current, to perform hardfloat operations. I decided to use the slackwareARM-current kernel (boot firmware and modules) on slackwareARM 14.2 userland and that got me roling 14.2 on the RPi 4.

Anyone that may need, for whatever reason, to run slackwareARM 14.2 on a RPi 4 may use this approach to work around the problem.

I then compiled the cross toolchain for AVR on the RPi 4 for using on the RPi Zero.

For those wondering why I wanted to do that:
The Arduino IDE for Linux ARM are hardfloat so they will not work on the only version of slackwareARM that can run on the RPi Zero , but the RPi Zero would actually make a nice small pocket combination for small Ardiono projects as it is not that much more expensive then a basic programmer for ATmega bare MCU, it can perform the actual initial upload of the Arduino bootloader (trough linuxgpio support in avrdude) and it is comparable size to the USBtiny programmer, but is a fully functional computer that can also compile the code to load into the Arduino.

AFAIK, the kernel is Floating Point (HF/SF) agnostic and only the tool chain (compilers) dictates how the binaries get compiled. On Slackware ARM 14.2 armv6 the whole system, including tool chain, is SoftFloat, meaning you could use whatever kernel you like, that is compatible with the SoC architecture (ARM code), even a 64bit one. I'm also compiling stuff on Pi2B for my PiZeroes and I'm actually using the Slackware ARM 14.2 armv6 loaded SDCard from the PiZero (which also contains the armv7 kernel) and booting it on the Pi2B, compiling the stuff, shutting down the PI2B and inserting it back in the PiZero.

My experience with the Raspberries ends at Pi2/Pi3 and never considered to get a Pi4, because I don't know if I could use it in a stable mode, not overheating & throttling (maybe forcing its frequency at 600Mhz).
Not sure the officially provided Slackware ARM -current kernel is the best (most compatible) solution to run on Raspberry, given this discussion (and the diarrhea from the last pages, you could save yourself from):
https://www.linuxquestions.org/quest...nt-4175647925/
I observed that the boot procedure changed a little for the Pi4 (some new files), wondering if extracting and using the "boot stuff" from a actual Raspbian image could provide a better solution. Much like what is documented here:
https://docs.slackware.com/howtos:ha...rm:raspberrypi

(On this occasion, I'd also like to thank you for one of your (very) older posts where you first documented the "boot stuff" extraction from Raspbian, a post that convinced me to buy my first Raspberry board)

You're welcome ... I also wrote most of the manual installation on slackware docs to be used when SARPI might not work
My first installation on RPi had-to go that way because I had a variant that would not boot with Fatdog's kernel and boot firmware: that'e why I wote that guide, just in case someone else gets unlucky and has a variant not yet supported by SARPI.
You have a point there: I have one of those all aluminium heat-sink fanless case for my RPi4 and it still gets pretty hot if I start compiling (and I took a great deal of care to make a metal shim so that I would have really good thermal contact between CPU and case). I ended up putting a fan on it but the USB3 ports make it appealing for making a cheap home NAS.