@eluxa Steps to follow for normal, not-patched, stock firmware:
Step 1:
Start by adding my Umbrel app store
Step 2:
install Knots (BLAKE2b) Companion
Step 3:
Let it complete the IBD
Step 4:
Install Datum (BLAKE2b) Companion
Step 5:
Launch the UI for Datum (BLAKE2b) Companion
Step 6:
Open the Config tab
Step 7:
For “Extranonce2 size” select “4 bytes Obelisk SC1 Gen2”
Step 8:
Click “Save”
Step 9:
Configure your ASIC to point to Datum (BLAKE2b) Companion
Ok i followed step by step all 9 datum says “ERROR: Could not fetch new template!” im assuming b/c bitcoin knots pruned is not yet fully synced that is why its showing new template yet. I will give it more time. I will let you guys know in the morning if this works. thank you
The test and logs confirms Paul’s fallback works on your real patched SC1-2 hardware.
Timeline from datum-gateway/datum.log:
07:51:18 — SC1-2 (192.168.1.118, cgminer/4.10.0) connected.
07:52:11 — the exact signal we were looking for: “Client 192.168.1.118/cgminer/4.10.0 submits a 32-bit extranonce2 in an 8-byte field; zero-extending it for this connection.” That’s the fallback detecting the 4-real-bytes-plus-4-garbage-bytes submission on its first share.
07:52:12 — Share accepted (NONCE a91d07da), immediately after the zero-extension.
07:53:30 and 07:53:57 — two more shares accepted.
07:53:31 — “Server stats: 1 client / 0.89 Th/s”.
So the miner is connected, hashing at ~0.89 Th/s, and shares are being accepted by the pool. The fallback latched correctly and only logged the zero-extension event once, as designed.
Correct, it won’t serve blocks during the IBD.
Hey Paul took a day in a half for knots companion to load and now it gives me an error: I dont know what is going on.
2026-09-19T00:10:58Z Included configuration file umbrel-bitcoin.conf
2026-09-19T00:10:58Z Bitcoin Knots version v29.4.1.knots20260508 (release build)
2026-09-19T00:10:58Z ParameterInteraction: parameter interaction: -walletimplicitsegwit=0 → setting -addresstype=legacy
2026-09-19T00:10:58Z Using the ‘arm_shani(1way;2way)’ SHA256 implementation
2026-09-19T00:10:58Z Default data directory /home/node/.bitcoin
2026-09-19T00:10:58Z Using data directory /data
2026-09-19T00:10:58Z Config file: /data/bitcoin.conf
2026-09-19T00:10:58Z R/W Config file: /data/bitcoin_rw.conf (not found, skipping)
2026-09-19T00:10:58Z Config file arg: acceptnonstddatacarrier=“0”
2026-09-19T00:10:58Z Config file arg: bantime=“86400”
2026-09-19T00:10:58Z Config file arg: blockfilterindex=“0”
2026-09-19T00:10:58Z Config file arg: blockmaxsize=“3985000”
2026-09-19T00:10:58Z Config file arg: blockmaxweight=“3985000”
2026-09-19T00:10:58Z Config file arg: blockmintxfee=“0.00001000”
2026-09-19T00:10:58Z Config file arg: blocknotify=“curl -s -m 5 http://paulscode-datum-blake2b_gateway_1:7152/NOTIFY”
2026-09-19T00:10:58Z Config file arg: blockreconstructionextratxn=“32768”
2026-09-19T00:10:58Z Config file arg: blockreconstructionextratxnsize=“10”
2026-09-19T00:10:58Z Config file arg: chain=“main”
2026-09-19T00:10:58Z Config file arg: coinstatsindex=“0”
2026-09-19T00:10:58Z Config file arg: datacarrier=“1”
2026-09-19T00:10:58Z Config file arg: datacarriercost=“1”
2026-09-19T00:10:58Z Config file arg: datacarriersize=“83”
2026-09-19T00:10:58Z Config file arg: dbcache=“3000”
2026-09-19T00:10:58Z Config file arg: i2pacceptincoming=“0”
2026-09-19T00:10:58Z Config file arg: i2psam=“10.21.22.63:7656”
2026-09-19T00:10:58Z Config file arg: includeconf=“umbrel-bitcoin.conf”
2026-09-19T00:10:58Z Config file arg: incrementalrelayfee=“0.00001000”
2026-09-19T00:10:58Z Config file arg: listen=“1”
2026-09-19T00:10:58Z Config file arg: listenonion=“0”
2026-09-19T00:10:58Z Config file arg: maxconnections=“125”
2026-09-19T00:10:58Z Config file arg: maxmempool=“300”
2026-09-19T00:10:58Z Config file arg: maxorphantx=“100”
2026-09-19T00:10:58Z Config file arg: maxreceivebuffer=“5000”
2026-09-19T00:10:58Z Config file arg: maxscriptsize=“1650”
2026-09-19T00:10:58Z Config file arg: maxsendbuffer=“5000”
2026-09-19T00:10:58Z Config file arg: maxuploadtarget=“0”
2026-09-19T00:10:58Z Config file arg: mempoolexpiry=“336”
2026-09-19T00:10:58Z Config file arg: minrelaytxfee=“0.00001000”
2026-09-19T00:10:58Z Config file arg: onion=“10.21.22.62:9050”
2026-09-19T00:10:58Z Config file arg: onlynet=“ipv4”
2026-09-19T00:10:58Z Config file arg: onlynet=“ipv6”
2026-09-19T00:10:58Z Config file arg: onlynet=“onion”
2026-09-19T00:10:58Z Config file arg: onlynet=“i2p”
2026-09-19T00:10:58Z Config file arg: peerblockfilters=“0”
2026-09-19T00:10:58Z Config file arg: peerbloomfilters=“0”
2026-09-19T00:10:58Z Config file arg: peertimeout=“60”
2026-09-19T00:10:58Z Config file arg: permitbaredatacarrier=“0”
2026-09-19T00:10:58Z Config file arg: permitbaremultisig=“0”
2026-09-19T00:10:58Z Config file arg: permitbarepubkey=“0”
2026-09-19T00:10:58Z Config file arg: persistmempool=“1”
2026-09-19T00:10:58Z Config file arg: prune=“4768”
2026-09-19T00:10:58Z Config file arg: rejectparasites=“1”
2026-09-19T00:10:58Z Config file arg: rejecttokens=“0”
2026-09-19T00:10:58Z Config file arg: rest=“0”
2026-09-19T00:10:58Z Config file arg: rpcallowip=“10.21.0.0/16”
2026-09-19T00:10:58Z Config file arg: rpcallowip=“127.0.0.1”
2026-09-19T00:10:58Z Config file arg: rpcauth=****
2026-09-19T00:10:58Z Config file arg: rpcworkqueue=“128”
2026-09-19T00:10:58Z Config file arg: timeout=“5000”
2026-09-19T00:10:58Z Config file arg: txindex=“0”
2026-09-19T00:10:58Z Config file arg: zmqpubhashblock=“tcp://0.0.0.0:48344”
2026-09-19T00:10:58Z Config file arg: zmqpubhashtx=“tcp://0.0.0.0:48346”
2026-09-19T00:10:58Z Config file arg: zmqpubrawblock=“tcp://0.0.0.0:48342”
2026-09-19T00:10:58Z Config file arg: zmqpubrawtx=“tcp://0.0.0.0:48343”
2026-09-19T00:10:58Z Config file arg: zmqpubsequence=“tcp://0.0.0.0:48345”
2026-09-19T00:10:58Z Config file arg: [main] bind=“0.0.0.0:18444”
2026-09-19T00:10:58Z Config file arg: [main] bind=“10.21.21.62:18334=onion”
2026-09-19T00:10:58Z Config file arg: [main] port=“18444”
2026-09-19T00:10:58Z Config file arg: [main] rpcbind=“10.21.21.62”
2026-09-19T00:10:58Z Config file arg: [main] rpcbind=“127.0.0.1”
2026-09-19T00:10:58Z Config file arg: [main] rpcport=“18443”
2026-09-19T00:10:58Z Config file arg: [main] whitebind=“0.0.0.0:18445”
2026-09-19T00:10:58Z Command-line arg: datadir=“/data”
2026-09-19T00:10:58Z Using at most 125 automatic connections (524288 file descriptors available)
2026-09-19T00:10:58Z scheduler thread start
2026-09-19T00:10:58Z Binding RPC on address 10.21.21.62 port 18443
2026-09-19T00:10:58Z Binding RPC on address 127.0.0.1 port 18443
2026-09-19T00:10:58Z Generated RPC authentication cookie /data/.cookie
2026-09-19T00:10:58Z Permissions used for cookie: rw-------
2026-09-19T00:10:58Z Using random cookie authentication.
2026-09-19T00:10:58Z Using rpcauth authentication.
2026-09-19T00:10:58Z Starting HTTP server with 16 worker threads
2026-09-19T00:10:58Z Using wallet directory /data
2026-09-19T00:10:58Z init message: Verifying wallet(s)…
2026-09-19T00:10:58Z Using /16 prefix for IP bucketing
2026-09-19T00:10:58Z init message: Loading P2P addresses…
2026-09-19T00:10:58Z Loaded 58925 addresses from peers.dat 577ms
2026-09-19T00:10:58Z init message: Loading banlist…
2026-09-19T00:10:58Z SetNetworkActive: true
2026-09-19T00:10:58Z Cache configuration:
2026-09-19T00:10:58Z * Using 2.0 MiB for block index database
2026-09-19T00:10:58Z * Using 8.0 MiB for chain state database
2026-09-19T00:10:58Z * Using 2990.0 MiB for in-memory UTXO set (plus up to 286.1 MiB of unused mempool space)
2026-09-19T00:10:58Z Script verification uses 3 additional threads
2026-09-19T00:10:58Z Using obfuscation key for blocksdir *.dat files (/data/blocks): ‘4bfccc9e75d7b8ee’
2026-09-19T00:10:58Z Opening LevelDB in /data/blocks/index
2026-09-19T00:10:58Z Opened LevelDB successfully
2026-09-19T00:10:58Z Using obfuscation key for /data/blocks/index: 0000000000000000
2026-09-19T00:10:58Z Using 16 MiB out of 16 MiB requested for signature cache, able to store 524288 elements
2026-09-19T00:10:58Z Using 16 MiB out of 16 MiB requested for script execution cache, able to store 524288 elements
2026-09-19T00:10:58Z init message: Loading block index…
2026-09-19T00:10:58Z Assuming ancestors of block 0000000000000078ed1e20cac1acf78df6d1060c78059fb6331e17141c881fc8 have valid signatures.
2026-09-19T00:10:58Z Setting nMinimumChainWork=00000000000000000000000000000000000000013e00277374c9f9eeadc70200
2026-09-19T00:10:58Z Prune configured to target 4768 MiB on disk for block and undo files.
2026-09-19T00:11:05Z LoadBlockIndexDB: last block file = 5691
2026-09-19T00:11:05Z LoadBlockIndexDB: last block file info: CBlockFileInfo(blocks=55, size=92808754, heights=961428…961579, time=2026-08-07…2026-08-08)
2026-09-19T00:11:05Z Checking all blk files are present…
2026-09-19T00:11:06Z LoadBlockIndexDB(): Block files have previously been pruned
2026-09-19T00:11:07Z Initializing chainstate Chainstate [ibd] @ height -1 (null)
2026-09-19T00:11:07Z Opening LevelDB in /data/chainstate
2026-09-19T00:11:08Z Opened LevelDB successfully
2026-09-19T00:11:08Z Using obfuscation key for /data/chainstate: d10b4f81e82c32a5
2026-09-19T00:11:08Z Leaving InitialBlockDownload (latching to false)
bitcoind: ./validation.cpp:3789: void Chainstate::PruneBlockIndexCandidates(): Assertion `!setBlockIndexCandidates.empty()’ failed.
The log indicates your server is a 4-core ARM device. What model device are you running Umbrel on, and how much RAM does it have?
There is a web archive holding most of the original documentaion for the Obeleisk miners
Thanks, I updated my question. Was asking about the Umbrel server that eluxa is running.
Im running umbrel node 16g ram 2tb m.2. I do have knots on, elecrum on it and mem pool before i installed yours the knots before installing yours in not pruned. do i need to change something in my settings?
Ok that Obelisk support by objectus does not work, it gives you links to download a scanner to wayback machine and those links lead you to nowhere. error messages saying no url found. ive tried those links before and now same thing. it would be nice to get that scanner but you can finde one anywhere. No URL has been captured for this URL prefix.
Cool, I was looking at OOM as a potential issue, but 16 GB should be enough. Let me see if I can find another possible cause. I think most folks don’t use ARM devices as servers so there may be idiosyncrasies with that architectre that need to be considered.
Hey paul got the node running and connect the datum companion pool is connected everything but its denying all shars and im sure on 4 obelisk gen 2 not the 8 says H not zero and denies all shares
Hey Paul i know its been some time but ive been really wanting to get my obelisk fixed and i dont even know how to began fixing it but his is what i found. Please help it looks like your Companion datum is running on old version? because right now i went to look for the version and typed that in to umbrel and it gave me this version is 0.4.1
Checking datum_gateway v0.4.1-beta commit
That’s the problem. v0.4.1-beta is the OCEAN-xyz original gateway (commit 5b06123, Jan 2026) — it does not contain the Blake2b H1 commitment fix. You need a CONVOY/Blockvase fork build.
And even some CONVOY builds are now being refused by pools on purpose — a Horizon-btc issue filed yesterday (Oct 5) confirms that build ac9b70c8 (which also reports as v0.4.1-beta/…) is being rejected. The current working baseline is CONVOYMining/datum_gateway PR #10, commit 7491a509.
Your options, easiest first:
If you’re on StartOS: Sideload the Blockvase DATUM Gateway 0.4.1.1 package from innerhat-dev/datum-gateway-startos (built from CONVOY commit 5060f3d). Or use the Maveth pow_0.4.1_19 package if you need the multi-out coinbaser fix.
If you’re on Umbrel: The Umbrel DATUM app is on v0.4.1-beta-hotfix.2 (Aug 25, 2026) — check whether that build includes the CONVOY fix. If you’re still getting rejections after updating, you’ll need to sideload.
If you’re building from source: Clone CONVOYMining/datum_gateway (not OCEAN-xyz/datum_gateway) and build from commit 7491a509 or later.
TL;DR: Your v0.4.1-beta is the wrong fork. Switch to a CONVOY/Blockvase build at commit 7491a509+ and the H-not-zero rejections should stop.
Haven’t looked at Datum Gateway in a while. They are actively breaking things over there at a rapid rate, and I’ve been focused on Lightning Fork (I only have so many hours in the evenings). I’ll get to updating it soon.
Thank you so much, i know how hard it can be, i work 10 - 12 a day and when i comeback from work try to attend to some mining eqpt few hours before sleep, kids and wife. But anyways thank you