Attention is currently required from: Angel Pons, Peter Farley. Nico Huber has posted comments on this change. ( https://review.coreboot.org/c/flashrom/+/63798 )
Change subject: ft2232_spi: Reduce read size for FT232H ......................................................................
Patch Set 1:
(1 comment)
Commit Message:
https://review.coreboot.org/c/flashrom/+/63798/comment/6a47f435_67a9ea3b PS1, Line 9: FT232H-based devices are unable to read over 256 bytes of flash in one
ftdi_read_data: -1, usb bulk read failed
Hmmm, looks at least like something one could debug further in libftdi. I'm also on Arch and just updated libftdi and libusb to the latest, still works...
There are two possible issues to consider: Is the amount of data limited per MPSSE_DO_READ command or per individual USB transfer.
For the latter there's a max-packet-size in the USB descriptor (see `lsusb -v` mine says "wMaxPacketSize 0x0200 1x 512 bytes" for both IN and OUT endpoints). However, this is something the USB stack should take care of (if the descriptor is valid).
I've played around with ftdi_read_data_set_chunksize(). This limits the size of transfers libftdi requests from libusb. It actually only works as long as I keep it above and a multiple of 512.