BeaglePlay bootable microSD

General Discussion
1

I’m trying to produce a bootable microSD card for the BeaglePlay from scratch without success. I can’t seem to get the processor ROM boot to recognize tiboot3.bin on the microSD card.

I was able to wipe the eMMC and then copy tiboot3.bin to /dev/mmcblk0boot0 without any problem, so booting from eMMC works fine. But I need to be able to also boot from microSD by holding down the user button as well, in case eMMC gets bricked.

I’ve made the FAT32 partition on the microSD card bootable and tried copying either of tiboot3.bin and TIBOOT3.BIN immediately after formatting. I’ve even tried writing tiboot3.bin to sector 8192 (0x400000, the raw mode redundant image offset).

Also I can’t reconcile the boot mode pins between the BeaglePlay schematic and the AM62x Technical Reference. For instance, I can’t find anything that pulls BOOTMODE2 low to get 25 MHz reference clock.

2

After a lot of very tedious experimentation today, I’ve learned some things about booting a BeaglePlay from microSD:

  1. The ROM boot code is very picky: It refuses to load tiboot3.bin from the 8 GB Kingston microSDHC card I was using. I eventually switched to a 32 GB ONN card, exactly the same as what I installed my reference Debian distribution to, and lo, the BeaglePlay now boots from microSD. None of 1 and 2 GB microSD’s I routinely use for Raspberry Pi’s work in the BeaglePlay. A Toshiba 32-GB card booted to Linux but the kernel refuses to recognize it. A SanDisk 400 GB card does not work.
  2. The ROM boot code is very picky: It refuses to load tiboot3.bin if the DOS partition starts at sector 16. Starting at sector 2048, as Linux fdisk now defaults to, works.
  3. tiboot3.bin refuses to load tispl.bin from an SD card with more than 32 sectors per cluster. For a 64-GB SD card, mkdosfs defaults to 64 sectors per cluster.

I use a script to format and populate boot media for Raspberry Pi’s and now the BeaglePlay. I have now edited that script to correct for items 2 and 3 and quit using the 8 GB card and now all is well. Hopefully this will help the next person trying to build custom boot media for the BeaglePlay.

1 Like