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First: If you can load a kernel into memory and execute the image, userland tools are not required. However, without said userland you would need to interface with the kernel API directly which means writing everything in very low level C. In practical terms, a typical boot process for Arm is to load a boot program (e.g. uboot, barebox) from a known location on a persistent media (e.g. sd card), which then sets up the hardware and pulls the kernel into memory and executes it. No userland necessary.

As per the history, Peter MacDonald was/is largely recognized as having created the first 'usable' GNU/Linux distribution.  https://en.wikipedia.org/wiki/Peter_MacDonald_(computer_programmer)  https://en.wikipedia.org/wiki/Softlanding_Linux_System

From memory of some discussions I had with him: Peter was working as a Unix systems administrator for the government and going to the University of Victoria for a Masters Degree. Peter wanted a way to work from home, but the Unix desktop license costs were prohibitive. He was already familiar with the GNU userland tools so when he saw Linus Torvalds' message on the University network he took full advantage and wired GNU tools to the new kernel. So really, the initial problem was the reverse of your question: The userland already existed and all that was needed was a kernel.

Some other historical tidbits:

• Peter did not distribute SLS Linux and did not charge a fee for the software. SLS was distributed by his wife Colleen and the fee was for the expensive and time consuming process of burning CDs to mail out.
• Peter made a number of huge contributions to the kernel that have never been acknowledged including dynamic module loading and improved memory management.
• The software was 'buggy' because he was working, going to school, raising two children and trying to keep Linux users happy. We all know how easy it is to keep Linux users happy...
• Peter has no recollection of the 'argument'/'disagreement' over installer scripts that others have claimed caused a rift that started Slackware and Debian.

Edited: Removed embarrassing lack of understand of how kernels work and left the important part.

The GNU userland existed before the Linux kernel did.

https://en.wikipedia.org/wiki/GNU

https://en.wikipedia.org/wiki/Linux_kernel

Peter MacDonald is largely recognized as having created the first 'usable' GNU/Linux distribution. 

https://en.wikipedia.org/wiki/Peter_MacDonald_(computer_programmer) 

https://en.wikipedia.org/wiki/Softlanding_Linux_System

From memory of some discussions I had with him: Peter was working as a Unix systems administrator for the government and going to the University of Victoria for a Masters Degree. Peter wanted a way to work from home, but the Unix desktop license costs were prohibitive. He was already familiar with the GNU userland tools so when he saw Linus Torvalds' message on the University network he took full advantage and wired GNU tools to the new kernel. So really, the initial problem was the reverse of your question: The userland already existed and all that was needed was a kernel.

Some other historical tidbits:

• Peter did not distribute SLS Linux and did not charge a fee for the software. SLS was distributed by his wife Colleen and the fee was for the expensive and time consuming process of burning CDs to mail out.
• Peter made a number of huge contributions to the kernel that have never been acknowledged including dynamic module loading and improved memory management.
• The software was 'buggy' because he was working, going to school, raising two children and trying to keep Linux users happy. We all know how easy it is to keep Linux users happy...
• Peter has no recollection of the 'argument'/'disagreement' over installer scripts that others have claimed caused a rift that started Slackware and Debian.

First: If you can load a kernel into memory and execute the image, userland tools are not required. However, without said userland you would need to interface with the kernel API directly which means writing everything in very low level C. In practical terms, a typical boot process for Arm is to load a boot program (e.g. uboot, barebox) from a known location on a persistent media (e.g. sd card), which then sets up the hardware and pulls the kernel into memory and executes it. No userland necessary.

As per the history, Peter MacDonald was/is largely recognized as having created the first 'usable' GNU/Linux distribution. https://en.wikipedia.org/wiki/Peter_MacDonald_(computer_programmer) https://en.wikipedia.org/wiki/Softlanding_Linux_System

From memory of some discussions I had with him: Peter was working as a Unix systems administrator for the government and going to the University of Victoria for a Masters Degree. Peter wanted a way to work from home, but the Unix desktop license costs were prohibitive. He was already familiar with the GNU userland tools so when he saw Linus Torvalds' message on the University network he took full advantage and wired GNU tools to the new kernel. So really, the initial problem was the reverse of your question: The userland already existed and all that was needed was a kernel.

Some other historical tidbits:

• Peter did not distribute SLS Linux and did not charge a fee for the software. SLS was distributed by his wife Colleen and the fee was for the expensive and time consuming process of burning CDs to mail out.
• Peter made a number of huge contributios to the kernel that have never been acknowledged including dynamic module loading and improved memory management.
• The software was 'buggy' because he was working, going to school, raising two children and trying to keep Linux users happy. We all know how easy it is to keep Linux users happy...
• Peter has no recollection of the 'argument'/'disagreement' over installer scripts that others have claimed caused a rift that started Slackware and Debian.

First: If you can load a kernel into memory and execute the image, userland tools are not required. However, without said userland you would need to interface with the kernel API directly which means writing everything in very low level C. In practical terms, a typical boot process for Arm is to load a boot program (e.g. uboot, barebox) from a known location on a persistent media (e.g. sd card), which then sets up the hardware and pulls the kernel into memory and executes it. No userland necessary.

As per the history, Peter MacDonald was/is largely recognized as having created the first 'usable' GNU/Linux distribution. https://en.wikipedia.org/wiki/Peter_MacDonald_(computer_programmer) https://en.wikipedia.org/wiki/Softlanding_Linux_System

From memory of some discussions I had with him: Peter was working as a Unix systems administrator for the government and going to the University of Victoria for a Masters Degree. Peter wanted a way to work from home, but the Unix desktop license costs were prohibitive. He was already familiar with the GNU userland tools so when he saw Linus Torvalds' message on the University network he took full advantage and wired GNU tools to the new kernel. So really, the initial problem was the reverse of your question: The userland already existed and all that was needed was a kernel.

Some other historical tidbits:

• Peter did not distribute SLS Linux and did not charge a fee for the software. SLS was distributed by his wife Colleen and the fee was for the expensive and time consuming process of burning CDs to mail out.
• Peter made a number of huge contributions to the kernel that have never been acknowledged including dynamic module loading and improved memory management.
• The software was 'buggy' because he was working, going to school, raising two children and trying to keep Linux users happy. We all know how easy it is to keep Linux users happy...
• Peter has no recollection of the 'argument'/'disagreement' over installer scripts that others have claimed caused a rift that started Slackware and Debian.

First: If you can load a kernel into memory and execute the image, userland tools are not required. However, without said userland you would need to interface with the kernel API directly which means writing everything in very low level C. In practical terms, a typical boot process for Arm is to load a boot program (e.g. uboot, barebox) from a known location on a persistent media (e.g. sd card), which then sets up the hardware and pulls the kernel into memory and executes it. No userland necessary.

As per the history, Peter MacDonald was/is largely recognized as having created the first 'usable' GNU/Linux distribution. https://en.wikipedia.org/wiki/Peter_MacDonald_(computer_programmer) https://en.wikipedia.org/wiki/Softlanding_Linux_System

From memory of some discussions I had with him: Peter was working as a Unix systems administrator for the government and going to the University of Victoria for a Masters Degree. Peter wanted a way to work from home, but the Unix desktop license costs were prohibitive. He was already familiar with the GNU userland tools so when he saw Linus Torvalds' message on the University network he took full advantage and wired GNU tools to the new kernel. So really, the initial problem was the reverse of your question: The userland already existed and all that was needed was a kernel.

Some other historical tidbits:

• Peter did not distribute SLS Linux and did not charge a fee for the software. SLS was distributed by his wife Colleen and the fee was for the expensive and time consuming process of burning CDs to mail out.
• Peter made a number of huge contribution to the kernel that have never been acknowledge including dynamic module loading and improved memory management.
• The software was 'buggy' because he was working, going to school, raising two children and trying to keep Linux users happy. We all know how easy it is to keep Linux users happy...
• Peter has no recollection of the 'argument'/'disagreement' over installer scripts that others have claimed caused a rift that started Slackware and Debian.

First: If you can load a kernel into memory and execute the image, userland tools are not required. However, without said userland you would need to interface with the kernel API directly which means writing everything in very low level C. In practical terms, a typical boot process for Arm is to load a boot program (e.g. uboot, barebox) from a known location on a persistent media (e.g. sd card), which then sets up the hardware and pulls the kernel into memory and executes it. No userland necessary.

As per the history, Peter MacDonald was/is largely recognized as having created the first 'usable' GNU/Linux distribution. https://en.wikipedia.org/wiki/Peter_MacDonald_(computer_programmer) https://en.wikipedia.org/wiki/Softlanding_Linux_System

From memory of some discussions I had with him: Peter was working as a Unix systems administrator for the government and going to the University of Victoria for a Masters Degree. Peter wanted a way to work from home, but the Unix desktop license costs were prohibitive. He was already familiar with the GNU userland tools so when he saw Linus Torvalds' message on the University network he took full advantage and wired GNU tools to the new kernel. So really, the initial problem was the reverse of your question: The userland already existed and all that was needed was a kernel.

Some other historical tidbits:

• Peter did not distribute SLS Linux and did not charge a fee for the software. SLS was distributed by his wife Colleen and the fee was for the expensive and time consuming process of burning CDs to mail out.
• Peter made a number of huge contributios to the kernel that have never been acknowledged including dynamic module loading and improved memory management.
• The software was 'buggy' because he was working, going to school, raising two children and trying to keep Linux users happy. We all know how easy it is to keep Linux users happy...
• Peter has no recollection of the 'argument'/'disagreement' over installer scripts that others have claimed caused a rift that started Slackware and Debian.