Problem with debian stretch boot after installation

Immediately after install from usb stick, I was able to boot into the new installation on the uSD card. Subsequently, the boot fails because one of the parameters in the boot cmdline is /dev/sdb2. However, after removing the USB stick, the uSD is /dev/sda. So, subsequent boot attempt fails, then the uSD appears not to be seen by the boot process any more. Any suggestions on what to do???

Hmm...
Have you thought of loading Stretch to the emmc and blowing away the installed lubuntu?
I think that's where I'm gonna go.

Thomas has the right idea.
When I did the install to emmc I left the partitions as is and told the installer to format the non UEFI partition and use that as root.
ie: I think it was the custom option for the partitioner and I didn't touch the sizes at all.

I'd still like to know what AtomicPi is doing to make a partition invisible?
I guess, if I write to the emmc and trash it, I can stick in a uSD that will boot. :-)

I wrote another uSD (16gb) from the Stretch USB installer. After rebooting with the USB stick still in, I edited the /boot/grub/grub.cfg and changed occurrences of sdb2 with sda2. Next I used Applepi Baker to back up the uSD to a .iso file. I tested that to make sure it would boot, then I added the development files that I wanted on my installation to be able to compile things like kernels and linuxcnc and backed it up again. Now I have a uSD image that I can work from to create bootable stretch images (without having to spend hours reloading the development environment). The 16gb uSD is almost full so I will use Etcher to write a 32gb uSD to work from. I will just have to expand the partition and file system to fill the 32gb uSD.
Once I get a preempt_rt kernel working, I will consider writing the stuff to the emmc.