Progress!
Since the laptop had previously run the 4.4.x kernels, I downgraded the kernel to 4.4.91. This kernel boots reliably.
I found that the kernel panic could be eliminated by reducing the amount of memory available with mem=950M (the laptop has 1Gbyte).
Both of these point to the E1505 having some kind of memory problem. It may be a problem in reporting or allocating memory rather than a hardware failure.
As long as I don't encounter further problems, the E1505 can avoid the recycler.
Thanks for the comments!
Ed
