JumpDrive isn't working

[phytocube]

1. Is my host PC missing a driver? dmesg doesn't seem to have picked up any plugging/unplugging events while the phone is on and ostensibly booted into JumpDrive. lsusb likewise doesn't change with the phone connected or disconnected. If the kernel driver needed to detect a PinePhone running JumpDrive isn't installed/loaded by default on a typical Arch system, this could be a quick and easy fix.
   
2. Is it normal for JumpDrive to start with a blank screen? If not, how should I troubleshoot it? I've already downloaded the image twice with cache cleared, and the checksums match.
   
3. If all else fails, is there a way to have the eMMC reflashed more "manually?" I don't have much in the way of appropriate tools/equipment, though...
   

Thanks!

1:
no, jumpdrive should work by default drivers in both linux pc and windows pc. and lsusb should show something. although i found some kind of bug in linux pc, that shows sizes wrong, probably related to eject command, reboot fixes it.
2:
no. screen should display something. basically jumpdrive logo/picture.
3:
you could install o.s. into sdcard and maybe after that using this installed o.s. yet again install into emmc. if the images are same, uuid's might bring some confusion, be careful (hint blkid).

one serious hint though, use "sync" command after dd command, because linux system usually do not write data immediately to the mass media.

1, 2: I got JumpDrive to work after playing around with the block size on a lark. 64K worked, but I'm not sure if that was before or after I brought /proc/sys/vm/dirty_*_ratio down to 1% from 10% and 20%. Looking back, since it was probably a buffering issue, sync would indeed have worked just as well without possibly introducing host system-wide side-effects, although I watched the progress with atop and only ever ejected the SD card after write activity to /dev/sda dropped off the monitor.
3: Luckily, flashing the eMMC with JumpDrive finally worked, and the phone is now back to normal! Thanks for looking into this.

Addendum: I'll add that I somehow downloaded and flashed the PinePhonePro Manjaro image instead of the PinePhone one at some point, and the former doesn't seem to be bootable on a PinePhone in case this helps someone in the future.