Not sure if this is a bug, or a tip/trick, but here goes:
I downloaded the (current) ISO and burnt to a CD to do first boot of tinycore. [Edit: No I didn't burn it I went from ISO direct to USB]
Then I followed the menu steps to make a bootable USB stick, which worked ok.
[Edit: I used the Universal-USB-Installer which carries a listed entry for Tiny Core Linux]
But being a noob, I didn't realise a fundamental problem that happened, and this was preventing me from installing packages...
When the USB bootable was created it made the subdirectory cde (instead of tce)
When the USB was booted, the download path was set to "tmp" something, and the "Set" button only allowed to make the path /mnt/sda1/tce/optional, this could not be edited to be cde.
So...I put the stick into a windoze box, renamed cde to tce, then went into boot/isolinux and edited isolinux.cfg using WORDPAD (note do not use NOTEPAD), change append cde to be append tce, save in wordpad.
Put USB stick back in tinycore target, boots as before except now from tce path, and the apps folder correctly lights up correctly pointing to mnt/sda1/tce/optional, and downloaded onboot packages go into the correct place for startup.
1. Hope this helps others
2. Maybe the 'make USB' process can be altered to use tce instead, this took me quite a while to figure out as a tc noob
[Edit: I note now with benefit of hindsight and re-tracing my steps that I was not using the 'recommended' core2usb installer and so this issue was created by my own customised installation method, but since the Universal-USB-Installer does actually 'work' this post may still help others (end edit)]