cracked it - and posting from an efi usb stick boot on a dell latitude e6220
The problem might have been that the usb stick had one of those u3 partitions not readily visible to linux - neither u3-tool nor full-fat hdparm wanted to remove it, but I found a windows tool that seems to have done the trick. The problem may also have been that I did not load Xorg-7.6 and graphics-3.0.21-tinycore "onboot" and thus I was not getting any display previously.
Used gdisk to create 2 partitions:
$ gdisk -l /dev/sdb
GPT fdisk (gdisk) version 0.6.11
l
Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present
Found valid GPT with protective MBR; using GPT.
Disk /dev/sdb: 2006673 sectors, 979.8 MiB
Logical sector size: 512 bytes
Disk identifier (GUID): 7CF13D85-1AA7-427F-990C-F31663DCD1F0
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 2006639
Partitions will be aligned on 2-sector boundaries
Total free space is 0 sectors (0 bytes)
Number Start (sector) End (sector) Size Code Name
1 34 245793 120.0 MiB EF00 EFI System
2 245794 2006639 859.8 MiB 0700 Linux/Windows data
and:
$ sudo mkfs.vfat /dev/sdb1
$ sudo mke2fs /dev/sdb2
Used grub from bzr of a few days ago:
$ sudo grub-install --target=x86_64-efi --boot-directory=/mnt/sdb1/EFI/BOOT --efi-directory=/mnt/sdb1 --removable
..note that this will create /EFI/BOOT and copy files as follows:
/EFI/BOOT/BOOTX64.EFI
/EFI/BOOT/grub/grubenv
/EFI/BOOT/grub/x86_64-efi/*mod
/EFI/BOOT/grub/fonts/unicode.pf2
/EFI/BOOT/grub/locale
Used the following:
$ cat /mnt/sdb1/EFI/BOOT/grub/grub.cfg
menuentry "core" {
linux (hd1,gpt2)/boot/vmlinuz quiet noswap tce=sdb2 tz=GMT-4 blacklist=bcma blacklist=ssb blacklist=b43 text
initrd (hd1,gpt2)/boot/core.gz
}
..I didn't bother loading fonts, efi_gop, gfxterm, etc and things still seem to have worked.
In the F2 dell menu, you need to change from legacy (bios) boot to uefi, create a boot entry and navigate to /EFI/BOOT/BOOTX64.EFI - somewhat annoyingly it doesn't seem to remember this across boots...