You said you were waiting on some info from Globalscale. No worries. I think I have a fix for the mtd issue.
First, I have a confession. I am not an openwrt user. I've got the ultra running in Debian 11 with the 6.0 Linux kernel mainline. Assuming openwrt has it set up similarly, I was able to apply the .dts for the spi flash in armada-3720-espressobin-ultra.dts to the (for me) much more functional armada-3720-ccpe.dts. Since there is no upload, I'll pastebin the result: https://h0c.us/v/DpQh/r
Compiling this to a .dtb with make dtbs and pointing to it in /boot allowed me to read the environment using fw_printenv, pointing to /dev/mtd2 as expected.
I'll be more detailed... Although I don't have a ton of detail. Here is what I did:
I rebooted the device, and pressed a key to get into U-boot.
I typed the above gpio commands manually.
I then typed 'boot' to continue the boot process
No pcie device showing up.
To get it working again, I went back to a patched armada-3720-ccpe.dtb (that includes the fix for the mtd). For some reason with this other .dtb, the pcie comes right up.
Both the stock bootloader as well as mainline U-boot will do the same, DTB doesnt matter for the bootloader, all that adding gpio toggle does is resets the PCI card before booting, that has been working for me a long time
Also, we should share notes. Do you get these errors in your journalctl as well?
Oct 17 12:13:08 espressobin-ultra kernel: debugfs: Directory 'd0060900.xor' with parent 'dmaengine' already present!
Oct 17 12:13:08 espressobin-ultra kernel: Unsupported CPU frequency 1200 MHz
Oct 17 12:13:11 espressobin-ultra kernel: mv88e6085 d0032004.mdio-mii:03: p3: hw VLAN 1 already used by port 1 in br0
Oct 17 12:13:11 espressobin-ultra kernel: mv88e6085 d0032004.mdio-mii:03: p2: hw VLAN 1 already used by port 1 in br0
Oct 17 12:13:14 espressobin-ultra kernel: Bluetooth: hci0: unexpected event for opcode 0x0000