My progress has come this far:
1. Connect serial 3,3V USB-TTL device to board by soldering. A real RS232 port will only show garbage in your terminal, as voltages are inverted with the decades old standard.
2. Setting up a TFTP server, providing initramfs image from EasyAcc Wi-Stor Wizard 8800 OpenWRT techdata page.
3. When uboot started, i selected
1: Load system code to SDRAM via TFTP.
and started the image.
4. I made backups of uBoot, uBoot settings, factory and stock firmware with
dd if=/dev/mtd0 of=/tmp/mtd0.backup
dd if=/dev/mtd1 of=/tmp/mtd1.backup
dd if=/dev/mtd2 of=/tmp/mtd2.backup
dd if=/dev/mtd3 of=/tmp/mtd3.backup
the file sizes are 192, 64, 64, 3776 kB -> sums up to an exact 4MB.
5. Get the backup files off the device by SSH/WinSCPing into it.
Before this, SSH must be enabled by setting a password.
As no physical connection is open, with which you could transfer files, we need to enable WiFi.
uci set wireless.@wifi-device.disabled=0
uci commit wireless
Of course the client which loads the backups must have configured a working IP configuration.
You'll get an idea how to do this by helping yourself with
6. Flash a non-stock firmware to the device.
choose uBoot option:
2: Load system code then write to Flash via TFTP.
This is the point where i run into problems:
uBoot loader won't take any squashfs image larger than 3866624 Bytes (0x3B0000) = 4MB -192 -64 -64 kB
The provided sysupgrade squashfs image from the page mentioned in part 2 is too large and the bootloader will refuse to flash it. But i managed to flash a squashfs 17.01.2 LEDE image with a size of 3408044 Bytes (0x3400AC) onto the router. So far it will boot up, show partitions to save config and additional installed software.
WORKS this far. Saving settings is rebootsafe.
But things aren't optimal:
There's only about 500kB free space left to install software like luci, vpn, vnstat, adblock, dyndns or similar, which is really not much. Taking a look at the image file sizes, there should be about some 450kB -root -rootfs of space which are not used. I have no idea on how to compile an image which will leave me with extra flash space for some tools and drivers by setting fixed partition sizes.
And i am stuck at the point that i don't understand why the techdata page shows that flash size is 8MB, but after all i had to use image files which won't exceed 4MB flash size as the flash chip W25Q32BV probably is of 32Mbit/4Mbyte size.
I haven't had the guts to tamper with the uboot loader, as i suspect the 4MB limit might come from there?
I would be grateful for any clue.
(Last edited by molocho on 31 Aug 2017, 17:17)